Sheet-form connector and production method and application therefor

ABSTRACT

Disclosed herein are a sheet-like connector that electrode structures each having a front-surface electrode part small in diameter can be formed, a stable electrically connected state can be surely achieved even to a circuit device, on which electrodes have been formed at a small pitch, and the electrode structures are prevented from falling off from an insulating sheet to achieve high durability, and a production process and applications thereof. 
     The sheet-like connector of the invention has an insulating sheet and a plurality of electrode structures arranged in the insulating sheet and extending through in a thickness-wise direction of the insulating sheet. Each of the electrode structures is composed of a front-surface electrode part exposed to a front surfaces of the insulating sheet and projected from the front surface of the insulating sheet, a back-surface electrode part exposed to a back surface of the insulating sheet, a short circuit part continuously extending from the base end of the front-surface electrode part through the insulating sheet in the thickness-wise direction thereof and linked to the back-surface electrode part, and a holding part continuously extending from a base end portion of the front-surface electrode part outward along the front surface of the insulating sheet.

TECHNICAL FIELD

The present invention relates to a sheet-like connector suitable for usein a probe device for conducting electric connection to a circuit, forexample, an integrated circuit or the like in electrical inspection ofthe circuit, and a production process and applications thereof.

BACKGROUND ART

In electrical inspection of, for example, a wafer, on which a greatnumber of integrated circuits have been formed, or a circuit device,such as an electronic part such as a semiconductor device, a probe forinspection having inspection electrodes arranged in accordance with apattern corresponding to a pattern of electrodes to be inspected of acircuit device to be inspected is used. As such a probe for inspection,may be used that, on which inspection electrodes composed of pins orblades are arranged.

When the circuit device to be inspected is a wafer, on which a greatnumber of integrated circuits have been formed, it is however necessaryto arrange a very great number of inspection electrodes upon productionof a probe for inspection for inspecting the wafer, so that such a probefor inspection becomes extremely expensive. In addition, when the pitchof electrodes to be inspected is small, the production itself of theprobe for inspection becomes difficult. Further, since warpage generallyoccurs on wafers, and the condition of the warpage varies withindividual products (wafers), it is difficult in practice to stably andsurely bring each of inspection electrodes of the probe for inspectioninto contact with a great number of electrodes to be inspected in thewafer.

For the above reasons, in recent years, a probe comprising a circuitboard for inspection, on one surface of which a plurality of inspectionelectrodes have been formed in accordance with a pattern correspondingto a pattern of electrodes to be inspected, an anisotropicallyconductive sheet arranged on one surface of the circuit board forinspection and a sheet-like connector which is formed by arranging, in aflexible insulating sheet, a plurality of electrode structures eachextending through in a thickness-wise direction of the insulating sheet,and arranged on the anisotropically conductive sheet, has been proposedas a probe for inspection for inspecting integrated circuits formed on awafer (see, for example, the following Prior Art 1).

FIG. 49 is a cross-sectional view illustrating the construction of aconventional exemplary probe for circuit inspection, which is equippedwith a circuit board for inspection, an anisotropically conductive sheetand a sheet-like connector. In this probe for circuit inspection, isprovided the circuit board 85 for inspection having, on one surfacethereof, a great number of inspection electrodes 86 formed in accordancewith a pattern corresponding to a pattern of electrodes to be inspectedof a circuit board to be inspected. The sheet-like connector 90 isarranged on one surface of the circuit board 85 for inspection throughthe anisotropically conductive sheet 80.

The anisotropically conductive sheet 80 is a sheet exhibitingconductivity only in its thickness-wise direction or havingpressure-sensitive conductive conductor parts exhibiting conductivityonly in its thickness-wise direction when it is pressurized in thethickness-wise direction. As such anisotropically conductive sheets,those of various structures have been known. For example, the followingPrior Art 2, and the like disclose an anisotropically conductive sheet(hereinafter referred to as “dispersion type anisotropically conductivesheet”) obtained by uniformly dispersing metal particles in anelastomer, and the following Prior Art 3, and the like disclose ananisotropically conductive sheet (hereinafter referred to as “unevendistribution type anisotropically conductive sheet”) obtained byunevenly distributing particles of a conductive magnetic substance in anelastomer to form a great number of conductive parts extending in athickness-wise direction thereof and insulating parts for mutuallyinsulating them. Further, the following Prior Art 4, and the likedisclose an uneven distribution type anisotropically conductive sheetwith a difference in level defined between the surface of eachconductive part and an insulating part.

The sheet-like connector 90 has a flexible insulating sheet 91 composedof, for example a resin, and is formed by arranging, in this insulatingsheet 91, a plurality of electrode structures 95 each extending in athickness-wise direction of the insulating sheet in accordance with thepattern corresponding to the pattern of the electrodes to be inspectedof the circuit board to be inspected. Each of the electrode structures95 is formed by integrally connecting a projected front-surfaceelectrode part 96 exposed to a front surface of the insulating sheet 91and a plate-like back-surface electrode part 97 exposed to a backsurface of the insulating sheet 91 to each other through a short circuitpart 98 extending through in the thickness-wise direction of theinsulating sheet 91.

Such a sheet-like connector 90 is generally produced in the followingmanner.

As illustrated in FIG. 50( a), a laminate material 90A obtained byforming a metal layer on one surface of an insulating sheet 91 is firstprovided, and through-holes 98H each extending through in athickness-wise direction of the insulating sheet 91 are formed in theinsulating sheet 91 as illustrated in FIG. 50( b).

As illustrated in FIG. 50( c), a resist film 93 is then formed on themetal layer 92 on the insulating sheet 91, and an electroplatingtreatment is conducted by using the metal layer 92 as a commonelectrode, whereby metal deposit is filled into the through-holes 98H inthe insulating sheet 91 to form short circuit parts 98 integrally joinedto the metal layer 92, and at the same time, projected front-surfaceelectrode parts 96 integrally joined to the respective short circuitparts 98 are formed on the front surface of the insulating sheet 91.

Thereafter, the resist film 93 is removed from the metal layer 92, andas illustrated in FIG. 50( d), a resist film 94A is formed on thesurface of the insulating sheet 91 including the front-surface electrodeparts 96, and moreover resist film portions 94B are formed on the metallayer 92 in accordance with a pattern corresponding to a pattern ofback-surface electrode parts to be formed. The metal layer 92 issubjected to an etching treatment to remove exposed portions of themetal layer 92, thereby forming back-surface electrode parts 97 asillustrated in FIG. 50( e), thus resulting in the formation of theelectrode structures 95.

The resist film 94A formed on the insulating sheet 91 and front-surfaceelectrode parts 96 is removed, and at the same time the resist filmportions 94B formed on the back-surface electrode parts 97 are removed,thereby obtaining the sheet-like connector 90.

In the above-described probe for inspection, the front-surface electrodeparts 96 of the electrode structures 95 in the sheet-like connector 90are arranged on the surface of a circuit board to be inspected, forexample, a wafer so as to be located on electrodes to be inspected ofthe wafer. In this state, the wafer is pressed by the probe forinspection, whereby the anisotropically conductive sheet 80 is pressedby the back-surface electrode parts 97 of the electrode structures 95 inthe sheet-like connector 90, and in the anisotropically conductive sheet80, conductive paths are thereby formed between the back-surfaceelectrode parts 97 and the inspection electrodes 86 of the circuit board85 for inspection in the thickness-wise direction of the anisotropicallyconductive sheet 80. As a result, electrical connection of theelectrodes to be inspected of the wafer to the inspection electrodes 86of the circuit board 85 for inspection is achieved. In this state,necessary electrical inspection as to the wafer is then performed.

According to such a probe for inspection, the anisotropically conductivesheet is deformed according to the degree of warpage of the wafer whenthe wafer is pressed by the probe for inspection, so that goodelectrical connection to a great number of the respective electrodes tobe inspected in the wafer can be surely achieved.

However, the above-described probe for inspection involves the followingproblems.

In the step of forming the short circuit parts 98 and front-surfaceelectrode parts 96 in the production process of the sheet-likeconnector, the metallic deposit by the electroplating isotropicallygrows. Therefore, in the resulting front-surface electrode part 96, adistance w from a periphery of the front-surface electrode part 96 to aperiphery of the short circuit part 98 becomes equivalent to theprojected height h of the front-surface electrode part 96 as illustratedin FIG. 51. Accordingly, the diameter R of the resulting front-surfaceelectrode part 96 exceeds twice of the projected height h and becomesconsiderably large. When the electrodes to be inspected in the circuitboard to be inspected are minute and arranged at an extremely smallpitch, a clearance between electrode structures 95 adjacent to eachother thus cannot be sufficiently retained. As a result, in theresulting sheet-like connector, the flexibility by virtue of theinsulating sheet 91 is lost, so that it is difficult to achieve stableelectrical connection to the circuit board to be inspected.

In addition, since it is difficult in practice to supply a current evenin current density distribution to the overall surface of the metallayer 92 in the electroplating treatment, the growing rate of themetallic deposit varies with individual through-holes 98H in theinsulating sheet 91 due to the unevenness of the current densitydistribution, so that a wide scatter occurs on the projected height h ofthe front-surface electrode parts 96 formed and the distance w from theperiphery of the front-surface electrode part 96 to the periphery of theshort circuit part 98, i.e., the diameter R. If a wide scatter occurs onthe projected height h of the front-surface electrode parts 96, stableelectrical connection to the circuit board to be inspected becomesdifficult. If a wide scatter occurs on the diameter of the front-surfaceelectrode parts 96 on the other hand, there is a possibility thatadjacent front-surface electrode parts may short-circuit each other.

In the above, a means of making the projected height h of thefront-surface electrode parts 96 small, and a means of making thediameter (smallest length in the case where the sectional form is notcircular) r of the short circuit parts 98 small, i.e., making thediameter of the through-holes 98H in the insulating sheet 91 small areconsidered as means for making the diameter of the resultingfront-surface electrode parts 96 small. In the sheet-like connectorobtained by the former means, however, it is difficult to surely achievestable electrical connection to the electrodes to be inspected. On theother hand, in the latter means, the formation itself of the shortcircuit parts 98 and front-surface electrode parts 96 by theelectroplating treatment becomes difficult.

In order to solve such problems, a sheet-like connector obtained byarranging a great number of electrode structures each having a taperedfront-surface electrode part, the diameter of which becomes graduallysmall from the base end toward the tip end, is proposed in the followingPrior Art 5 and Prior Art 6.

The sheet-like connector described in the following Prior Art 5 isproduced in the following manner.

As illustrated in FIG. 52( a), a laminate material 90B obtained byforming a resist film 93A and a front surface-side metal layer 92A on afront surface of an insulating sheet 91 in this order, and laminating aback surface-side metal layer 92B on a back surface of the insulatingsheet 91 is provided. As illustrated in FIG. 52( b), through-holes eachlinked to each of the back surface-side metal layer 92B, insulatingsheet 91 and resist film 93A in the laminate material 90B and extendingin a thickness-wise direction of the laminate material are formed,thereby forming, in the back surface of the laminate material 90B,recesses 90K for forming electrode structures, which each have a taperedform fitted to a short circuit part and a front-surface electrode partof an electrode structure to be formed. As illustrated in FIG. 52( c), aplating treatment is then conducted by using the front surface-sidemetal layer 92A in the laminate material 90B as an electrode, therebyfilling a metal into the recesses 90K for forming electrode structuresto form front-surface electrode parts 96 and short circuit parts 98. Theback surface-side metal layer in the laminate material is then subjectedto an etching treatment to remove a part thereof, thereby formingback-surface electrode parts 97 as illustrated in FIG. 52( d), thusresulting in provision of the sheet-like connector.

The sheet-like connector described in the following Prior Art 6 isproduced in the following manner.

As illustrated in FIG. 53( a), a laminate material 90C obtained byforming a front surface-side metal layer 92A on a front surface of aninsulating sheet material 91A having a thickness greater than that of aninsulating sheet in a sheet-like connector to be formed and laminating aback surface-side metal layer 92B on a back surface of the insulatingsheet material 91A is provided. As illustrated in FIG. 53( b),through-holes each linked to each of the back surface-side metal layer92B and insulating sheet material 91A in the laminate material 90C andextending in a thickness-wise direction of the laminate material areformed, thereby forming, in the back surface of the laminate material90C, recesses 90K for forming electrode structures, which each have atapered form fitted to a short circuit part and a front-surfaceelectrode part of an electrode structure to be formed. A platingtreatment is then conducted by using the front surface-side metal layer92A in the laminate material 90C as an electrode, thereby filling ametal into the recesses 90K for forming electrode structures asillustrated in FIG. 53( c) to form front-surface electrode parts 96 andshort circuit parts 98. Thereafter, the front surface-side metal layer92A in the laminate material 90C is removed, and the insulating sheetmaterial 91A is subjected to an etching treatment to remove the portionon the front surface side of the insulating sheet material, therebyforming an insulating sheet 91 having a necessary thickness- andexposing the front-surface electrode parts 96 as illustrated in FIG. 53(d). The back surface-side metal layer 92B is then subjected to anetching treatment, thereby forming back-surface electrode parts, thusresulting in provision of the sheet-like connector.

According to such a sheet-like connector, the front-surface electrodeparts small in diameter and high in projected height can be formed in astate that a clearance between front-surface electrodes of electrodestructures adjacent to each other has been sufficiently retained, sincethe front-surface electrode parts are in a tapered form. In addition,the front-surface electrode parts of the respective electrode structuresare formed by using the recesses for forming the electrode structuresformed in the laminate material as cavities, so that the electrodestructures narrow in a scatter of projected height of the front-surfaceelectrode parts can be provided.

In these sheet-like connectors, however, the diameter of thefront-surface electrode parts in the electrode structures is equivalentto or smaller than the diameter of the short circuit parts, i.e., thediameter of the through-holes formed in the insulating sheet, so thatthe electrode structures fall off from the back surface of theinsulating sheet, resulting in the difficulty of actually using such asheet-like connector.

Prior Art 1: Japanese Patent Application Laid-Open No. 231019/1995;

Prior Art 2: Japanese Patent Application Laid-Open No. 93393/1976;

Prior Art 3: Japanese Patent Application Laid-Open No. 147772/1978;

Prior Art 4: Japanese Patent Application Laid-Open No. 250906/1986;

Prior Art 5: Japanese Patent Application Laid-Open No. 326378/1999;

Prior Art 6: Japanese Patent Application Laid-Open No. 2002-196018.

DISCLOSURE OF THE INVENTION

The present invention has been made on the basis of the foregoingcircumstances and has as a first object the provision of a sheet-likeconnector that electrode structures each having a front-surfaceelectrode part small in diameter can be formed, and a stableelectrically connected state can be surely achieved even to a circuitdevice, on which electrodes have been formed at a small pitch, and theelectrode structures are prevented from falling off from an insulatingsheet to achieve high durability.

A second object of the present invention is to provide a process capableof producing a sheet-like connector that electrode structures eachhaving a front-surface electrode part small in diameter and narrow in ascatter of projected height thereof can be formed, and stableelectrically connected state can be surely achieved even to a circuitdevice, on which electrodes have been formed at a small pitch, and theelectrode structures are prevented from falling off from an insulatingsheet to achieve high durability.

A third object of the present invention is to provide a probe forcircuit inspection, which is equipped with the above-describedsheet-like connector.

A fourth object of the present invention is to provide an inspectionapparatus for circuit devices, which is equipped with theabove-described probe for circuit inspection.

According to the present invention, there is provided a sheet-likeconnector comprising an insulating sheet and a plurality of electrodestructures arranged in the insulating sheet in a state separated fromone another in a plane direction of the insulating sheet and extendingthrough in a thickness-wise direction of the insulating sheet,

wherein each of the electrode structures is composed of a front-surfaceelectrode part exposed to a front surface of the insulating sheet andprojected from the front surface of the insulating sheet, a back-surfaceelectrode part exposed to a back surface of the insulating sheet, ashort circuit part continuously extending from the base end of thefront-surface electrode part through the insulating sheet in thethickness-wise direction thereof and linked to the back-surfaceelectrode part, and a holding part continuously extending from a baseend portion of the front-surface electrode part outward along the frontsurface of the insulating sheet.

In the sheet-like connector according to the present invention, thefront-surface electrode part in the electrode structure may preferablyhave a shape that the diameter becomes gradually small from the base endthereof toward the tip end.

The value of a ratio R₂/R₁ of the diameter R₂ of the tip end of thefront-surface electrode part in the electrode structure to the diameterR₁ of the base end of the front-surface electrode part may preferably be0.11 to 0.55.

The value of a ratio h/R₁ of the projected height h of the front-surfaceelectrode part in the electrode structure to the diameter R₁ of the baseend of the front-surface electrode part may preferably be 0.2 to 3.

The short circuit part in the electrode structure may have a shape thatthe diameter becomes gradually small from the back surface of theinsulating sheet toward the front surface thereof.

The insulating sheet may be composed of preferably an etching-capablepolymeric material, particularly preferably polyimide.

According to the present invention, there is provided a process forproducing the sheet-like connector described above, which comprises thesteps of:

providing a laminate material having at least an insulating sheet, afirst front surface-side metal layer formed on a front surface of theinsulating sheet, an insulating layer formed on the surface of the firstfront surface-side metal layer and a second front surface-side metallayer formed on the surface of the insulating layer,

forming through-holes linked to each of the insulating sheet, firstfront surface-side metal layer and insulating layer in the laminatematerial and extending in a thickness-wise direction of the laminatematerial, thereby forming, in the back surface of the laminate material,recesses for forming electrode structures,

subjecting the laminate material to a plating treatment by using thesecond front surface-side metal layer as an electrode, thereby filling ametal into the recesses for forming electrode structures to formfront-surface electrode parts projected from the front surface of theinsulating sheet and short circuit parts continuously extending from therespective base ends of the front-surface electrode parts through theinsulating sheet in a thickness-wise direction thereof,

removing the second front surface-side metal layer and insulating layerfrom the laminate material, thereby exposing the front-surface electrodeparts and the first front surface-side metal layer, and then

subjecting the first front surface-side metal layer to an etchingtreatment, thereby forming holding parts continuously extending from abase end portion of the front-surface electrode part outward along thefront surface of the insulating sheet.

In the production process of the sheet-like connector according to thepresent invention, the through-hole in the insulating layer in therecesses for forming the electrode structures may preferably be formedin a form that the diameter becomes gradually small from the backsurface of the insulating layer toward the front surface thereof.

In such a production process of the sheet-like connector, it may bepreferable that a laminate material that the insulating layer thereof isformed of an etching-capable polymeric material be used as the laminatematerial, and the through-hole in the insulating layer in the recessesfor forming the electrode structures be formed by etching.

In the production process of the sheet-like connector according to thepresent invention, the through-hole in the insulating sheet in therecesses for forming the electrode structures may preferably be formedin a form that the diameter becomes gradually small from the backsurface of the insulating sheet toward the front surface thereof.

In such a production process of the sheet-like connector, it may bepreferable that a laminate material that the insulating sheet thereof isformed of an etching-capable polymeric material be used as the laminatematerial, and the through-hole in the insulating sheet in the recessesfor forming the electrode structures be formed by etching.

According to the present invention, there is provided a process forproducing the sheet-like connector described above, which comprises thesteps of:

providing a laminate material having at least an insulating sheet, afront surface-side metal layer formed on a front surface of theinsulating sheet, an insulating layer formed on the surface of the frontsurface-side metal layer and a back surface-side metal layer formed on aback surface of the insulating sheet,

forming through-holes linked to each of the insulating layer, frontsurface-side metal layer and insulating sheet in the laminate materialand extending in a thickness-wise direction of the laminate material,thereby forming, in the front surface of the laminate material, recessesfor forming electrode structures,

subjecting the laminate material to a plating treatment by using theback surface-side metal layer as an electrode, thereby filling a metalinto the recesses for forming electrode structures to form front-surfaceelectrode parts projected from the front surface of the insulating sheetand short circuit parts continuously extending from the respective baseends of the front-surface electrode parts through the insulating sheetin a thickness-wise direction thereof,

removing the insulating layer from the laminate material, therebyexposing the front-surface electrode parts and the front surface-sidemetal layer, and then

subjecting the front surface-side metal layer to an etching treatment,thereby forming holding parts continuously extending from a base endportion of the front-surface electrode part outward along the frontsurface of the insulating sheet.

According to the present invention, there is provided a probe forcircuit inspection for conducting electrical connection between acircuit device that is an object of inspection and a tester, whichcomprises:

a circuit board for inspection, on which a plurality of inspectionelectrodes have been formed according to electrodes to be inspected of acircuit device, which is an object of inspection, an anisotropicallyconductive connector arranged on the circuit board for inspection, andthe above-described sheet-like connector arranged on the anisotropicallyconductive connector.

In the probe for circuit inspection according to the present invention,it may be preferable that when the circuit device that is the object ofinspection is a wafer, on which a great number of integrated circuitshave been formed, and the anisotropically conductive connector shouldhave a frame plate having a plurality of openings formed correspondinglyto electrode regions, in which electrodes to be inspected in the wholeor part of the integrated circuits formed on the wafer, which is theobject of inspection, have been arranged, and anisotropically conductivesheets arranged so as to close the respective openings in the frameplate.

According to the present invention, there is provided an inspectionapparatus for circuit devices, which comprises the above-described probefor circuit inspection.

EFFECTS OF THE INVENTION

According to the sheet-like connector of the present invention, theholding part continuously extending from a base end portion of thefront-surface electrode part outward along the front surface of theinsulating sheet is formed in each of the electrode structures, so thatthe electrode structures are prevented from falling off from theinsulating sheet to achieve high durability even when the diameter ofthe front-surface electrode parts is small.

In addition, the front-surface electrode parts small in diameter can beformed, whereby a clearance between adjacent front-surface electrodescan be surely retained, and so flexibility by virtue of the insulatingsheet can be sufficiently exhibited. As a result, a stable electricallyconnected state can be surely achieved even to a circuit device, onwhich electrodes have been formed at a small pitch.

According to the production process of the sheet-like connectoraccording to the present invention, the recesses for forming theelectrode structures are formed in the laminate material having theinsulating sheet in advance, and the front-surface electrode parts areformed by using the recesses for forming the electrode structures ascavities, so that the front-surface electrode parts small in diameterand narrow in a scatter of the projected height can be provided.

In addition, the holding parts continuously extending from the base endportion of the front-surface electrode part outward along the frontsurface of the insulating sheet can be surely formed by subjecting thefront surface-side metal layer formed on the front surface of theinsulating sheet to an etching treatment, so that a sheet-like connectorhas a high durability as the electrode structures are prevented fromfalling off from the insulating sheet can be produced even when thediameter of the front-surface electrode parts is small.

According to the probe for circuit inspection according to the presentinvention, the above-described sheet-like connector is provided, so thata stable electrically connected state can be surely achieved even to acircuit device, on which electrodes have been formed at a small pitch.In addition, since the electrode structures in the sheet-like connectorare prevented from falling off, high durability is achieved.

According to the inspection apparatus for circuit devices, theabove-described probe for circuit inspection is provided, so that astable electrically connected state can be surely achieved even to acircuit device, on which electrodes have been formed at a small pitch.In addition, inspection can be performed with high reliability over along period of time even when the inspection is conducted as to a greatnumber of circuit devices.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating the construction of afirst exemplary sheet-like connector according to the present invention.

FIG. 2 is a cross-sectional view illustrating, on an enlarged scale,electrode structures of the first exemplary sheet-like connector.

FIG. 3 is a cross-sectional view illustrating the construction of alaminate material for producing the first exemplary sheet-likeconnector.

FIG. 4 is a cross-sectional view illustrating a state that resist filmsfor etching have been formed on both surfaces of the laminate materialshown in FIG. 3.

FIG. 5 is a cross-sectional view illustrating a state that through-holeshave been formed in a back surface-side metal layer in the laminatematerial.

FIG. 6 is a cross-sectional view illustrating a state that through-holeshave been formed in an insulating sheet in the laminate material.

FIG. 7 is a cross-sectional view illustrating a state that through-holeshave been formed in a first front surface-side metal layer in thelaminate material.

FIG. 8 is a cross-sectional view illustrating a state that through-holeshave been formed in an insulating layer in the laminate material to formrecesses for forming electrode structures.

FIG. 9 is a cross-sectional view illustrating a state that resist filmsfor plating have been formed on both surfaces of the laminate material,in which the recesses for forming electrode structures were formed.

FIG. 10 is a cross-sectional view illustrating a state that a metal hasbeen filled into the recesses for forming electrode structures to formfront-surface electrode parts and short circuit parts.

FIG. 11 is a cross-sectional view illustrating a state that resist filmshave been formed on surface of back-surface electrode parts.

FIG. 12 is a cross-sectional view illustrating a state that portions ofthe back surface-side metal layer have been removed to form a pluralityof the back-surface electrode parts separated from one another.

FIG. 13 is a cross-sectional view illustrating a state that theinsulting layer has been removed from the laminate material.

FIG. 14 is a cross-sectional view illustrating a state that resist filmsfor etching have been formed on the surfaces of the first frontsurface-side metal layer and front-surface electrode parts.

FIG. 15 is a cross-sectional view illustrating a state that the firstfront surface-side metal layer has been subjected to an etchingtreatment to form holding parts.

FIG. 16 is a cross-sectional view illustrating the construction of asecond exemplary sheet-like connector according to the presentinvention.

FIG. 17 is a cross-sectional view illustrating the construction of alaminate material for producing the second exemplary sheet-likeconnector.

FIG. 18 is a cross-sectional view illustrating a state thatthrough-holes have been formed in an insulating layer in the laminatematerial shown in FIG. 17.

FIG. 19 is a cross-sectional view illustrating a state thatthrough-holes have been formed in a front surface-side metal layer inthe laminate material.

FIG. 20 is a cross-sectional view illustrating a state thatthrough-holes have been formed in an insulating sheet in the laminatematerial to form recesses for forming electrode structures.

FIG. 21 is a cross-sectional view illustrating a state that a metal hasbeen filled into the recesses for forming electrode structures to formconductors for front-surface electrode parts, and short circuit parts.

FIG. 22 is a cross-sectional view illustrating a state that theinsulting layer has been removed from the laminate material.

FIG. 23 is a cross-sectional view illustrating a state that resist filmsfor etching have been formed on the surfaces of the front surface-sidemetal layer and the conductors for front-surface electrode parts.

FIG. 24 is a cross-sectional view illustrating a state that the frontsurface-side metal layer has been subjected to an etching treatment toform holding parts.

FIG. 25 is a cross-sectional view illustrating a state that theconductors for front-surface electrode parts have been subjected to anelectrolytic etching treatment to form front-surface electrode parts.

FIG. 26 is a cross-sectional view illustrating a state that a patternedresist film for etching has been formed on the surface of a backsurface-side metal layer, and a resist film for etching has been formedon the surfaces of an insulating sheet, the front-surface electrodeparts and holding parts.

FIG. 27 is a cross-sectional view illustrating a state that the backsurface-side metal layer has been removed to form back-surface electrodeparts.

FIG. 28 is a cross-sectional view illustrating the construction of athird exemplary sheet-like connector according to the present invention.

FIG. 29 is a cross-sectional view illustrating the construction of alaminate material for producing the third exemplary sheet-likeconnector.

FIG. 30 is a cross-sectional view illustrating a process for formingrecesses for forming electrode structures in the laminate material shownin FIG. 29.

FIG. 31 is a cross-sectional view illustrating a state that resist filmsfor plating have been formed on both surfaces of the laminate material,in which the recesses for forming electrode structures were formed.

FIG. 32 is a cross-sectional view illustrating a state that a metal hasbeen filled into the recesses for forming electrode structures.

FIG. 33 is a cross-sectional view illustrating a state that resist filmsfor etching have been formed on the respective surfaces of a secondfront surface-side metal layer, back-surface electrode parts and backsurface-side metal layer.

FIG. 34 is a cross-sectional view illustrating a state that the secondfront surface-side metal layer has been subjected to an etchingtreatment to form conductors for front-surface electrode parts having atop portion projected from a central portion.

FIG. 35 is a cross-sectional view illustrating a state that resist filmsfor etching have been formed on the surfaces of a first frontsurface-side metal layer and the conductors for front-surface electrodeparts.

FIG. 36 is a cross-sectional view illustrating a state that the firstfront surface-side metal layer has been subjected to an etchingtreatment to form holding parts.

FIG. 37 is a cross-sectional view illustrating a state that theconductors for front-surface electrode parts have been subjected to anelectrolytic etching treatment to form front-surface electrode parts.

FIG. 38 is a cross-sectional view illustrating a state that resist filmsfor etching have been formed on the surfaces of the back-surfaceelectrode parts, and a resist film for etching has been formed on thesurfaces of an insulating sheet, the front-surface electrode parts andthe holding parts.

FIG. 39 is a cross-sectional view illustrating a state that the backsurface-side metal layer has been removed to form the back-surfaceelectrode parts separated from one another.

FIG. 40 is a cross-sectional view illustrating the construction of afourth exemplary sheet-like connector according to the presentinvention.

FIG. 41 is a cross-sectional view illustrating the construction of anexemplary inspection apparatus for circuit devices according to thepresent invention.

FIG. 42 is a cross-sectional view illustrating, on an enlarged scale, aprobe for circuit inspection in the inspection apparatus shown in FIG.41.

FIG. 43 is a plan view of an anisotropically conductive connector in theprobe for circuit inspection shown in FIG. 42.

FIG. 44 is a plan view illustrating a wafer for test fabricated inExample.

FIG. 45 illustrates a position of a region of electrodes to be inspectedof integrated circuits formed on the wafer for test shown in FIG. 44.

FIG. 46 illustrates an arrangement pattern of the electrodes to beinspected of the integrated circuits formed on the wafer for test shownin FIG. 44.

FIG. 47 is a plan view illustrating a frame plate in an anisotropicallyconductive connector produced in Example.

FIG. 48 illustrates, on an enlarged scale, a part of the frame plateshown in FIG. 47.

FIG. 49 is a cross-sectional view illustrating the construction of aconventional exemplary probe for circuit inspection.

FIG. 50 is a cross-sectional view illustrating a conventional exemplaryproduction process of a sheet-like connector.

FIG. 51 is a cross-sectional view illustrating, on an enlarged scale, asheet-like connector in the probe for circuit inspection shown in FIG.49.

FIG. 52 is a cross-sectional view illustrating another conventionalexemplary production process of a sheet-like connector.

FIG. 53 is a cross-sectional view illustrating a further conventionalexemplary production process of a sheet-like connector.

[Description of Characters]  1 Probe for circuit inspection,  3Pressurizing plate,  4 Wafer-mounting table,  5 Heater,  6 Wafer,  7Electrodes to be inspected, 10 Sheet-like connector, 10A, 10B Laminatematerials, 10K Recesses for forming electrode structures, 11 Insulatingsheet, 11H Through-holes, 12A, 12B, 12C, 12D, 12E Resist films, 13, 13A,13B, 13C, 13D Resist films, 13K Patterned holes, 14A, 14B, 14C Resistfilms, 14K Patterned holes, 15 Electrode structures, 16 Front-surfaceelectrode parts, 16B Insulating layer, 16A Second front surface-sidemetal layer, 16H Through-holes, 16M Conductors for front-surfaceelectrode parts, 17 Back-surface electrode parts, 17A Back surface-sidemetal layer, 17H Through-holes, 18 Short circuit parts, 19 Holdingparts, 19A First front surface-side metal layer, 19B Front surface-sidemetal layer, 19H Through-holes, 20 Circuit board for inspection, 21Inspection electrodes, 30 Anisotropically conductive connector, 31 Frameplate, 32 Openings, 33 Air inflow holes, 35 Anisotropically conductivesheet, 36 Conductive parts, 37 Insulating parts, 38 Projected portions,80 Anisotropically conductive sheet, 85 Circuit board for inspection, 86Inspection electrodes, 90 Sheet-like connector, 90A, 90B, 90C Laminatematerials, 90K Recesses for forming electrode structures, 91 Insulatingsheet, 91A Insulating sheet material, 92, 92A, 92B Metal Layers, 93, 93AResist films, 94A, 94B Resist films, 95 Electrode structures, 96Front-surface electrode parts, 97 Back-surface electrode parts, 98 Shortcircuit parts, 98H Through-holes, L Integrated circuits, P Conductiveparticles.

BEST MODE FOR CARRYING OUT THE INVENTION

The embodiments of the present invention will hereinafter be describedin details.

[Sheet-Like Connector]

FIG. 1 is a cross-sectional view illustrating the construction of afirst exemplary sheet-like connector according to the present invention,and FIG. 2 is a cross-sectional view illustrating, on an enlarged scale,electrode structures in the first exemplary sheet-like connector.

The first exemplary sheet-like connector 10 is used in a probe forconducting electrical inspection of circuit devices and has a flexibleinsulating sheet 11. In the insulating sheet 11, a plurality ofelectrode structures 15 composed of a metal and extending in athickness-wise direction of the insulating sheet 11 are arranged in astate separated from one another in a plane direction of the insulatingsheet 11 in accordance with a pattern corresponding to a pattern ofelectrodes to be inspected of a circuit device that is an object ofinspection.

Each of the electrode structures 15 is composed of a protrudingfront-surface electrode part 16 exposed to a front surface of theinsulating sheet 11 and projected from the front surface of theinsulating sheet 11, a rectangular flat plate-like back-surfaceelectrode part 17 exposed to a back surface of the insulating sheet 11,a short circuit part 18 continuously extending from the base end of thefront-surface electrode part 16 through the insulating sheet 11 in thethickness-wise direction thereof and linked to the back-surfaceelectrode part 17, and a circular ring plate-like holding part 19continuously extending from a peripheral surface of a base end portionof the front-surface electrode part 16 outward and radially along thefront surface of the insulating sheet 11. In the electrode structure 15of this embodiment, each front-surface electrode part 16 is formedcontinuously with the short circuit part 18 in a tapered form that thediameter becomes gradually small as it goes toward a tip end from a baseend thereof, i.e., formed in a truncated cone form as a whole, and theshort circuit part 18 continuous with the base end of the front-surfaceelectrode part 16 is formed in a tapered form that the diameter becomesgradually small as it goes toward one surface from the other surface ofthe insulating sheet 11, i.e., formed in a truncated cone form as awhole. The diameter R₁ of the base end of the front-surface electrodepart 16 is the same as the diameter R₃ of an end of the short circuitpart 18 continuous with this base end.

No particular limitation is imposed on the insulating sheet 11 so far asit has insulating property and is flexible. For example, a resin sheetformed of a polyamide resin, liquid crystal polymer, polyester,fluororesin or the like, or a sheet obtained by impregnating a clothwoven by fibers with any of the above-described resins may be used.However, the insulating sheet is preferably composed of anetching-capable material in that through-holes for forming the shortcircuit parts 18 can be easily formed by etching with polyimide beingparticularly preferred.

No particular limitation is also imposed on the thickness d of theinsulating sheet 11 so far as such an insulating sheet 11 is flexible.However, it is preferably 10 to 50 μm, more preferably 10 to 25 μm.

As a metal for forming the electrode structures 15, may be used nickel,copper, gold, silver, palladium, iron or the like. The electrodestructures 15 may be any of those formed of a simple metal, those formedof an alloy of at least two metals and those obtained by laminating atleast two metals as a whole.

On the surfaces of the front-surface electrode part 16 and back-surfaceelectrode part 17 in the electrode structure 15, a film of a chemicallystable metal having high conductivity, such as gold, silver or palladiummay be formed in order that oxidation of the electrode parts may beprevented, and electrode parts small in contact resistance may beprovided.

In each electrode structure 15, a ratio (R₂/R₁) of the diameter R₂ ofthe tip end of the front-surface electrode part 16 to the diameter R₁ ofthe base end is preferably 0.11 to 0.55, more preferably 0.15 to 0.4. Bysatisfying such conditions, a stable electrically connected state to acircuit device to be connected is surely achieved even when the circuitdevice has minute electrodes at a small pitch.

The diameter R₁ of the base end of the front-surface electrode part 16is preferably 30 to 70%, more preferably 35 to 60% of the pitch of theelectrode structures 15.

A ratio h/R₁ of the projected height h of the front-surface electrodepart 16 to the diameter R₁ of the base end thereof is preferably 0.2 to0.8, more preferably 0.25 to 0.6. By satisfying such conditions,electrode structures 15 of a pattern corresponding to a pattern ofelectrodes of a circuit device to be connected can be easily formed evenwhen the circuit device has minute electrodes at a small pitch, andmoreover a stable electrically connected state to the circuit device ismore surely achieved.

The diameter R₁ of the base end of the front-surface electrode part 16is preset in consideration of the above-described conditions, thediameter of its corresponding electrode to be connected, and the like.However, it is, for example, preferably 30 to 80 μm, more preferably 30to 50 μm.

The projected height h of the front-surface part 16 is preferably 15 to50 μm, more preferably 15 to 30 μm in that stable electrical connectionto its corresponding electrode to be connected can be achieved.

The outer diameter R₅ of each back-surface electrode part 17 is onlyrequired to be greater than the diameter R₄ of the other end of theshort circuit part 18 linked to the back-surface electrode part 17 andsmaller than the pitch of the electrode structures 15 and is preferablygreat as much as possible. Stable electrical connection can be therebyachieved with certainty even to, for example, the anisotropicallyconductive sheet.

The thickness D₂ of the back-surface electrode part 17 is preferably 10to 40 μm, more preferably 15 to 35 μm in that sufficiently high strengthand excellent repetitive durability are achieved.

A ratio R₃/R₄ of the diameter R₃ of one end of the short circuit part 18to the diameter R₄ of the other end thereof is preferably 0.45 to 1,more preferably 0.7 to 0.9.

The diameter R₃ of one end of the short circuit part 18 is preferably 30to 70%, more preferably 35 to 60% of the pitch of the electrodestructures 15.

The diameter R₆ of each holding part 19 is preferably 30 to 70%, morepreferably 40 to 60% of the pitch of the electrode structures 15.

The thickness D₁ of the holding part 19 is preferably 3 to 12 μm, morepreferably 5 to 9 μm.

According to such a sheet-like connector 10, the holding part 19continuously extending from the base end portion of the front-surfaceelectrode part 16 outward along the front surface of the insulatingsheet 11 is formed in each of the electrode structures 15, so that theelectrode structures 15 are prevented from falling off from the backsurface of the insulating sheet 11 to achieve high durability even whenthe diameter of the front-surface electrode parts 16 is small.

In addition, the electrode structures each have the front-surfaceelectrode part 16 small in diameter, whereby a clearance betweenadjacent front-surface electrodes 16 can be surely retained, and soflexibility by virtue of the insulating sheet 11 can be sufficientlyexhibited. As a result, a stable electrically connected state can besurely achieved even to a circuit device, on which electrodes have beenformed at a small pitch.

The above-described first exemplary sheet-like connector 10 can beproduced, for example, in the following manner.

As illustrated in FIG. 3, a laminate material 10A composed of aninsulating sheet 11, a first front surface-side metal layer 19A formedon a front surface of the insulating sheet 11, an insulating layer 16Bformed on the surface of the first front surface-side metal layer 19A, asecond front surface-side metal layer 16A formed on the surface of theinsulating layer 16B, and a back surface-side metal layer 17A formed ona back surface of the insulating sheet 11 is first provided.

In the laminate material 10A, the first front surface-side metal layer19A is formed so as to have a thickness equivalent to the thickness of aholding part 19 in each of electrode structures 15 to be formed, theinsulating layer 16B is formed in such a manner that the total thicknessof a thickness of the insulating layer 16B and the thickness of thefirst front surface-side metal layer 19A is equivalent to the projectedheight of a front-surface electrode part 16 in the electrode structure15 to be formed, and the back surface-side metal layer 17A is formed soas to have a thickness smaller than the thickness of a back-surfaceelectrode part 17 in the electrode structure 15 to be formed.

As a material for forming the insulating sheet 11, a polymeric materialcapable of being etched is preferably used, with polyimide being morepreferred.

As a material for forming the insulating layer 16B, a polymeric materialcapable of being etched is preferably used, with polyimide being morepreferred.

Such a laminate material 10A can be obtained by providing a laminatedpolyimide sheet with metal layers composed of, for example, copperlaminated on both sides thereof and a laminated thermoplastic polyimidesheet with a metal layer composed of, for example, copper laminated onone side thereof, which are both generally marketed, arranging them insuch a manner that a surface of the laminated thermoplastic polyimidesheet, on which metal layer is not laminated, faces the surface of onemetal layer of the laminated polyimide sheet, and subjecting both sheetsto a pressure-bonding treatment under heat.

To such a laminate material 10A, as illustrated in FIG. 4, a resist film12A for etching is formed on the whole surface of the second frontsurface-side metal layer 16A, and a resist film 13 for etching, in whicha plurality of patterned holes 13K have been formed in accordance with apattern corresponding to a pattern of the electrode structures 15 to beformed, is formed on the surface of the back surface-side metal layer17A.

As materials for forming the resist films 12A and 13, may be usedvarious materials used as photoresists for etching.

Exposed portions of the back surface-side metal layer 17A are thensubjected to an etching treatment through the respective patterned holes13K in the resist film 13 to remove such portions, thereby forming, inthe back surface-side metal layer 17A, a plurality of through-holes 17Hlinked to the respective patterned holes 13K in the resist film 13 asillustrated in FIG. 5. Thereafter, exposed portions of the insulatingsheet 11 are subjected to an etching treatment through the respectivepatterned holes 13K in the resist film 13 and the respectivethrough-holes 17H in the back surface-side metal layer 17A to removesuch portions, thereby forming, in the insulating sheet 11, a pluralityof tapered through-holes 11H, the diameter of which becomes graduallysmall from the back surface of the insulating sheet 11 toward the frontsurface thereof, and each of which are linked to the through-holes 17Kin the back surface-side metal layer 17A as illustrated in FIG. 6.Thereafter, exposed portions of the first front surface-side metal layer19A are subjected to an etching treatment through the respectivepatterned holes 13K in the resist film 13, the respective through-holes17H in the back surface-side metal layer 17A and the respectivethrough-holes 11H in the insulating sheet 11 to remove such portions,thereby forming, in the first front surface-side metal layer 19A, aplurality of through-holes 19H each linked to the through-holes 11H inthe insulating sheet 11 as illustrated in FIG. 7. Further, exposedportions of the insulating layer 16B are subjected to an etchingtreatment through the respective patterned holes 13K in the resist film13, the respective through-holes 17H in the back surface-side metallayer 17A, the respective through-holes 11H in the insulating sheet 11and the respective through-holes 19H in the first front surface-sidemetal layer 19A to remove such portions, thereby forming, in theinsulating layer 16B, a plurality of tapered through-holes 16H, thediameter of which becomes gradually small from the back surface of theinsulating layer 16B toward the front surface thereof, and each of whichare linked to the respective through-holes 19H in the first frontsurface-side metal layer 19A as illustrated in FIG. 8. A plurality ofrecesses 10K for forming electrode structures each linked with therespective through-holes 17H in the back surface-side metal layer 17A,the respective through-holes 11H in the insulating sheet 11, therespective through-holes 19H in the first front surface-side metal layer19A and the respective through-holes 16H in the insulating layer 16Blinked to one another are thereby formed in the back surface of thelaminate material 10A.

Etchants for etching the back surface-side metal layer 17A and the firstfront surface-side metal layer in the above-described process aresuitably selected according to the materials forming these metal layers.When these metal layers are composed of, for example, copper, an aqueoussolution of ferric chloride may be used.

As an etchant for etching the insulating sheet 11 and the insulatinglayer 16B, may be used an aqueous hydrazine solution. The taperedthrough-holes 11H and 16H, the diameter of which becomes gradually smallfrom the back surface toward the front surface, can be formed in theinsulating sheet 11 and the insulating layer 16B, respectively, byselecting conditions for the etching treatments.

After the resist films 12A and 13 are removed from the laminate material10A, in which the recesses 10K for forming electrode structures havebeen formed in such a manner, as illustrated in FIG. 9, a resist film12B for plating is formed on the laminate material 10A so as to coverthe whole surface of the second front surface-side metal layer 16A, anda resist film 14A for plating, in which a plurality of patterned holes14K have been formed in accordance with a pattern corresponding to apattern of back-surface electrode parts 17 in the electrode structures15 to be formed, is formed on the surface of the back surface-side metallayer 17A.

As materials for forming the resist films 12B and 14A, may be usedvarious materials used as photoresists for plating.

The laminate material 10A is then subjected to an electroplatingtreatment by using the second front surface-side metal layer 16A as anelectrode to fill a metal into the respective recesses 10K for formingelectrode structures and the respective patterned holes 14K in theresist film 14A, thereby forming a plurality of protruding front-surfaceelectrode parts 16 projected from the front surface of the insulatingsheet 11, short circuit parts 18 continuously extending from therespective base ends of the front-surface electrode parts 16 through theinsulating sheet 11 in a thickness-wise direction thereof, andback-surface electrode parts 17 respectively linked to the other ends ofthe short circuit parts 18 as illustrated in FIG. 10. In this state, theback-surface electrode parts 17 are in a state connected to one anotherthrough the back surface-side metal layer 17A.

After the resist films 12B and 14A are removed from the laminatematerial 10A, in which the front-surface electrode parts 16, shortcircuit parts 18 and back-surface electrode parts 17 have been formed insuch a manner, a patterned resist film 14B for etching is formed so asto cover the back-surface electrode parts 17 to subject the second frontsurface-side metal layer 16A and the back surface-side metal layer 17Ato an etching treatment, thereby removing the whole of the second frontsurface-side metal layer 16A and exposed portions of the backsurface-side metal layer as illustrated in FIG. 12 to form a pluralityof back-surface electrode parts 17 separated from one another.

The insulating layer 16B is then subjected to an etching treatment toremove the whole thereof, and the resist film 14B is removed, therebyexposing the front-surface electrode parts 16, first front surface-sidemetal layer 19A and back-surface electrode parts 17 as illustrated inFIG. 13. Thereafter, as illustrated in FIG. 14, a patterned resist film12C for etching is formed so as to cover the front-surface electrodeparts 16 and portions to become holding parts 19 in the first frontsurface-side metal layers 19A, and a resist film 14C for etching isformed so as to cover the back surface of the insulating sheet 11 andall of the back-surface electrode parts 17. The first front surface-sidemetal layer 19A is then subjected to an etching treatment to removeexposed portions, thereby forming holding parts 19 each continuouslyextending from a peripheral surface of a base end portion of thefront-surface electrode part 16 outward and radially along the frontsurface of the insulating sheet 11, thus resulting in the formation ofthe electrode structures 15.

The resist films 12C is then removed from the front-surface electrodeparts 16 and holding parts 19, and the resist film 14C is removed fromthe back surface of the insulating sheet 11 and the back-surfaceelectrode parts 17, thereby obtaining the sheet-like connector 10 shownin FIG. 1.

According to such a process, the recesses 10K for forming the electrodestructures are formed in the laminate material 10A having the insulatingsheet 11 in advance, and the front-surface electrode parts 16 are formedby using the recesses 10K for forming the electrode structures ascavities, so that the front-surface electrode parts 16 small in diameterand narrow in a scatter of the projected height thereof can be provided.

In addition, the holding parts 19 each continuously extending from thebase end portion of the front-surface electrode part 16 outward alongthe front surface of the insulating sheet 11 can be surely formed bysubjecting the front surface-side metal layer 19A formed on the frontsurface of the insulating sheet 11 to an etching treatment, so that thesheet-like connector 10 that has high durability as the electrodestructures 15 are prevented from falling off from the insulating sheet11 can be produced even when the diameter of the front-surface electrodeparts 16 is small.

FIG. 16 is a cross-sectional view illustrating the construction of asecond exemplary sheet-like connector according to the presentinvention.

The second exemplary sheet-like connector 10 is used in a probe forconducting electrical inspection of circuit devices and has a flexibleinsulating sheet 11. In the insulating sheet 11, a plurality ofelectrode structures 15 composed of a metal and extending in athickness-wise direction of the insulating sheet 11 are arranged in astate separated from one another in a plane direction of the insulatingsheet 11 in accordance with a pattern corresponding to a pattern ofelectrodes to be inspected of a circuit device that is an object ofinspection.

Each of the electrode structures 15 is composed of a protrudingfront-surface electrode part 16 exposed to a front surface of theinsulating sheet 11 and projected from the front surface of theinsulating sheet 11, a rectangular flat plate-like back-surfaceelectrode part 17 exposed to a back surface of the insulating sheet 11,a columnar short circuit part 18 continuously extending from the baseend of the front-surface electrode part 16 through the insulating sheet11 in the thickness-wise direction thereof and linked to theback-surface electrode part 17, and a circular ring plate-like holdingpart 19 continuously extending from a peripheral surface of a base endportion of the front-surface electrode part 16 outward and radiallyalong the front surface of the insulating sheet 11. In the electrodestructure 15 of this embodiment, the top portion of each front-surfaceelectrode part 16 is formed in an almost semi-spherical shape that thediameter becomes small as it goes toward the tip thereof, and thediameter of the base end of the front-surface electrode part 16 isequivalent to the diameter of one end of the short circuit part 18continuous with the base end.

The above-described second exemplary sheet-like connector 10 can beproduced, for example, in the following manner.

As illustrated in FIG. 17, a laminate material 10B composed of aninsulating sheet 11 formed of a polymeric material capable being etched,for example, polyimide, a front surface-side metal layer 19B formed on afront surface of the insulating sheet 11, an insulating layer 16B formedon the surface of the front surface-side metal layer 19B, a backsurface-side metal layer 17A formed on a back surface of the insulatingsheet 11, and a resist film 13A formed on the back surface-side metallayer 17A is first provided.

In the laminate material 10B, the front surface-side metal layer 19B isformed so as to have a thickness equivalent to the thickness of aholding part 19 in each of electrode structures 15 to be formed, theinsulating layer 16B is formed in such a manner that the total thicknessof a thickness of the insulating layer 16B and the thickness of thefirst front surface-side metal layer 19B is equivalent to the projectedheight of a front-surface electrode part 16 in the electrode structure15 to be formed, and the back surface-side metal layer 17A is formed soas to have a thickness equivalent to the thickness of a back-surfaceelectrode part 17 in the electrode structure 15 to be formed.

The insulating layer 16B is then subjected to photolithography (exposingtreatment and developing treatment), thereby forming a plurality ofthrough-holes 16H in the insulating layer 16B in accordance with apattern corresponding to a pattern of front-surface electrode parts 16in the electrode structures 15 to be formed as illustrated in FIG. 18.Exposed portions of the front surface-side metal layer 19B are thensubjected to an etching treatment through the respective through-holes16H in the insulating layer 16B to remove such portions, therebyforming, in the front surface-side metal layer 19B, a plurality ofthrough-holes 19H each linked to the respective through-holes 16H in theinsulating layer 16B as illustrated in FIG. 19. Exposed portions of theinsulating sheet 11 are then subjected to an etching treatment throughthe respective through-holes 16H in the insulating layer 16B and therespective through-holes 19H in the front surface-side metal layer 19Bto remove such portions, thereby forming, in the insulating sheet 11, aplurality of through-holes 11H each linked to the respectivethrough-holes 19H in the front surface-side metal layer 19B asillustrated in FIG. 20. A plurality of recesses 10K for formingelectrode structures with the respective through-holes 16H in theinsulating layer 16B, the respective through-holes 19H in the frontsurface-side metal layer 19B and the respective through-holes 11H in theinsulating sheet 11 linked to one another are thereby formed in thefront surface of the laminate material 10B.

The laminate material 10B, in which the recesses 10K for formingelectrode structures have been formed in such a manner, is subjected toan electroplating treatment by using the back surface-side metal layer17A as an electrode to fill a metal into the respective recesses 10K forforming electrode structures, thereby forming a plurality of columnarconductors 16M for front-surface electrode parts, which are projectedfrom the front surface of the insulating sheet 11, and short circuitparts 18 continuously extending from the respective base ends of theconductors 16M for front-surface electrode parts through the insulatingsheet 11 in a thickness-wise direction thereof and linked to the backsurface-side metal layer 17A as illustrated in FIG. 21.

The insulating layer 16B is removed from the laminate material 10B, inwhich the conductors 16M for front-surface electrode parts and shortcircuit parts 18 have been formed in such a manner, thereby exposing theconductors 16M for front-surface electrode parts and front surface-sidemetal layer 19B as illustrated in FIG. 22. A patterned resist film 13Bis then formed so as to cover the conductors 16M for front-surfaceelectrode parts and portions to become holding parts 19 in the frontsurface-side metal layer 19B as illustrated in FIG. 23. The frontsurface-side metal layer 19B is then subjected to an etching treatmentto remove exposed portions, thereby forming holding parts 19 eachcontinuously extending from a peripheral surface of a base end portionof the conductor 16M for front-surface electrode part outward andradially along the front surface of the insulating sheet 11 asillustrated in FIG. 24. After the resist film 13B is then removed toexpose the respective conductors 16M for front-surface electrode partsand the respective holding parts 19, an electrolytic etching treatmentis conducted to shape the respective conductors 16M for front-surfaceelectrode parts, thereby forming front-surface electrode parts 16 eachhaving a top portion in an almost semi-spherical form as illustrated inFIG. 25.

The resist film 13A on the back surface of the insulating sheet 11 isthen subjected to photolithography, thereby forming a patterned resistfilm 13D so as to cover portions to become back-surface electrode partsin the back surface-side metal layer 17A and forming a resist film 13Cso as to cover the front surface of the insulating sheet 11, thefront-surface electrode parts 16 and the holding parts 19 as illustratedin FIG. 26. The back surface-side metal layer 17A is then subjected toan etching treatment to remove exposed portions, thereby formingback-surface electrode parts 17 respectively linked to the other ends ofthe short circuit parts 18 as illustrated in FIG. 27, thus resulting inthe formation of the electrode structures 15.

The resist film 13C is then removed from the insulating sheet 11,front-surface electrode parts 16 and holding part 19, and the resistfilm 13D is removed from the back-surface electrode parts 17, therebyobtaining the second exemplary sheet-like connector 10 shown in FIG. 16.

According to such a second exemplary sheet-like connector, the sameeffects as in the first exemplary sheet-like connector are achieved.

FIG. 28 is a cross-sectional view illustrating the construction of athird exemplary sheet-like connector according to the present invention.

The third exemplary sheet-like connector 10 is used in a probe forconducting electrical inspection of circuit devices and has a flexibleinsulating sheet 11. In the insulating sheet 11, a plurality ofelectrode structures 15 composed of a metal and extending in athickness-wise direction of the insulating sheet 11 are arranged in astate separated from one another in a plane direction of the insulatingsheet 11 in accordance with a pattern corresponding to a pattern ofelectrodes to be inspected of a circuit device that is an object ofinspection.

Each of the electrode structures 15 is composed of a protrudingfront-surface electrode part 16 exposed to a front surface of theinsulating sheet 11 and projected from the front surface of theinsulating sheet 11, a back-surface electrode part 17 exposed to a backsurface of the insulating sheet 11, a columnar short circuit part 18continuously extending from the base end of the front-surface electrodepart 16 through the insulating sheet 11 in the thickness-wise directionthereof and linked to the back-surface electrode part 17, and a circularring plate-like holding part 19 continuously extending from a peripheralsurface of a base end portion of the front-surface electrode part 16outward and radially along the front surface of the insulating sheet 11.In the electrode structure 15 of this embodiment, the front-surfaceelectrode part 16 has an almost semi-spherical central portion, thediameter of which becomes small toward the tip end side from the baseend side thereof, and an almost semi-spherical tip portion having adiameter smaller than the diameter of the central portion, the diameterof which becomes small toward the tip. The diameter of the base end ofthe front-surface electrode part 16 is equivalent to the diameter of oneend of the short circuit part 18 continuous with the base end. On theother hand, the back-surface electrode part 17 has a rectangular flatplate-like base portion and a rectangular flat plate-like tip portionprojected from this base portion and a size smaller than the baseportion.

The above-described third exemplary sheet-like connector 10 can beproduced, for example, in the following manner.

As illustrated in FIG. 29, a laminate material 10A composed of aninsulating sheet 11 formed of a polymeric material capable of beingetched, for example, polyimide, a first front surface-side metal layer19A formed on a front surface of the insulating sheet 11, an insulatinglayer 16B formed on the surface of the first front surface-side metallayer 19A and formed of a polymeric material capable of being etched,for example, polyimide, a second front surface-side metal layer 16Aformed on the surface of the insulating layer 16B, and a backsurface-side metal layer 17A formed on a back surface of the insulatingsheet 11 is first provided.

In the laminate material 10A, the first front surface-side metal layer19A is formed so as to have a thickness equivalent to the thickness of aholding part 19 in each of electrode structures 15 to be formed, theinsulating layer 16B is formed so as to have a thickness equivalent tothe thickness (height) of the central portion of the front-surfaceelectrode part 19 in the electrode structure 15 to be formed, the secondfront surface-side metal layer 16A is formed so as to have a thicknessequivalent to the thickness (height) of the tip portion of thefront-surface electrode part 19 in the electrode structure 15 to beformed, and the back surface-side metal layer 17A is formed so as tohave a thickness equivalent to a base portion of a back-surfaceelectrode part 17 in the electrode structure 15 to be formed.

To such a laminate material 10A, as illustrated in FIG. 30( a), a resistfilm 12A for etching is formed on the whole surface of the second frontsurface-side metal layer 16A, and a resist film 13 for etching, in whicha plurality of patterned holes 13K have been formed in accordance with apattern corresponding to a pattern of the electrode structures 15 to beformed, is formed on the surface of the back surface-side metal layer17A.

Exposed portions of the back surface-side metal layer 17A are thensubjected to an etching treatment through the respective patterned holes13K in the resist film 13 to remove such portions, thereby forming aplurality of through-holes 17H in the back surface-side metal layer 17Aas illustrated in FIG. 30( b). Thereafter, exposed portions of theinsulating sheet 11 are subjected to an etching treatment through therespective patterned holes 13K in the resist film 13 and the respectivethrough-holes 17H in the back surface-side metal layer 17A to removesuch portions, thereby forming, in the insulating sheet 11, a pluralityof through-holes 11H each linked to the respective through-holes 17H inthe back surface-side metal layer 17A as illustrated in FIG. 30( c).Thereafter, exposed portions of the first front surface-side metal layer19A are subjected to an etching treatment through the respectivepatterned holes 13K in the resist film 13, the respective through-holes17H in the back surface-side metal layer 17A and the respectivethrough-holes 11H in the insulating sheet 11 to remove such portions,thereby forming, in the first front surface-side metal layer 19A, aplurality of through-holes 19H each linked to the respectivethrough-holes 11H in the insulating sheet 11 as illustrated in FIG. 30(d). Further, exposed portions of the insulating layer 16B are subjectedto an etching treatment through the respective patterned holes 13K inthe resist film 13, the respective through-holes 17H in the backsurface-side metal layer 17A, the respective through-holes 11H in theinsulating sheet 11 and the respective through-holes 19H in the firstfront surface-side metal layer 19A to remove such portions, therebyforming, in the insulating layer 16B, a plurality of through-holes 16Heach linked to the respective through-holes 19H in the first frontsurface-side metal layer 19A as illustrated in FIG. 30( e). A pluralityof recesses 10K for forming electrode structures with the respectivethrough-holes 17H in the back surface-side metal layer 17A, therespective through-holes 11H in the insulating sheet 11, the respectivethrough-holes 19H in the first front surface-side metal layer 19A andthe respective through-holes 16H in the insulating layer 16B linked toone another are thereby formed in the back surface of the laminatematerial 10A.

After the resist films 12A and 13 are removed from the laminate material10A, in which the recesses 10K for forming electrode structures havebeen formed in such a manner, as illustrated in FIG. 31, a resist film12B for plating is formed on the laminate material 10A so as to coverthe whole surface of the second front surface-side metal layer 16A, anda resist film 14A for plating, in which a plurality of patterned holes14K have been formed in accordance with a pattern corresponding to apattern of back-surface electrode parts 17 in the electrode structures15 to be formed, is formed on the surface of the back surface-side metallayer 17A.

The laminate material 10A is then subjected to an electroplatingtreatment by using the second front surface-side metal layer 16A as anelectrode to fill a metal into the respective recesses 10K for formingelectrode structures and the respective patterned holes 14K in theresist film 14A, thereby forming a plurality of protruding conductors16M for front-surface electrode parts projected from the front surfaceof the insulating sheet 11, short circuit parts 18 continuouslyextending from the respective base ends of the conductors 16M forfront-surface electrode parts through the insulating sheet 11 in athickness-wise direction thereof, and back-surface electrode parts 17respectively linked to the other ends of the short circuit parts 18 asillustrated in FIG. 32. In this state, each of the conductors 16M forfront-surface electrode parts are in a state connected to one anotherthrough the second front surface-side metal layer 16A, and each of theback-surface electrode parts 17 are in a state connected to one anotherthrough the back surface-side metal layer 17A.

After the resist films 12B and 14A are removed from the laminatematerial 10A, in which the conductors 16M for front-surface electrodeparts, short circuit parts 18 and back-surface electrode parts 17 havebeen formed in such a manner, as illustrated in FIG. 33, a resist film14C for etching is formed so as to cover the back-surface electrodeparts 17 and back surface-side metal layer 17A, and a patterned resistfilm 12D for etching is formed on the surface of the second frontsurface-side metal layer 16A in accordance with a pattern correspondingto a pattern of the tip portions of the front-surface electrode parts 16to be formed to subject the second front surface-side metal layer 16A toan etching treatment, thereby removing exposed portions to form aplurality of conductors 16M for front-surface electrode parts, whicheach have a columnar central portion and a tip portion having a diametersmaller than the diameter of the central portion and are separated fromone another, as illustrated in FIG. 34.

The resist film 12D is then removed, and the insulating layer 16B issubjected to an etching treatment to remove the whole thereof, therebyexposing the conductors 16M for front-surface electrode parts and thefirst front surface-side metal layer 19A. Thereafter, as illustrated inFIG. 35, a patterned resist film 12C for etching is formed so as tocover the conductors 16M for front-surface electrode parts and portionsto become holding parts 19 in the first front surface-side metal layer19A. The first front surface-side metal layer 19A is then subjected toan etching treatment to remove exposed portions, thereby forming aplurality of holding parts 19 each continuously extending from aperipheral surface of a base end portion of the conductor 16M forfront-surface electrode part outward and radially along the frontsurface of the insulating sheet 11 as illustrated in FIG. 36. After theresist films 12C are then removed to expose the conductors 16M for frontsurface electrode parts and holding parts 19, an electrolytic etchingtreatment is conducted to shape the conductors 16M for front surfaceelectrode parts, thereby forming front surface electrode parts 16 eachhaving an almost semi-spherical central portion and an almostsemi-spherical tip portion projected from the central portion asillustrated in FIG. 37.

The resist film 14C is then subjected to photolithography, therebyforming a patterned resist film 14B for etching so as to cover theback-surface electrode parts 17 as illustrated in FIG. 38, and a resistfilm 12E for etching is formed so as to cover the front surface of theinsulating sheet 11, the front-surface electrode parts 16 and theholding parts 19 to subject the back surface-side metal layer 17A to anetching treatment, thereby removing exposed portions to form a pluralityof back-surface electrode parts 17 separated from one another asillustrated in FIG. 39, thus resulting in the formation of the electrodestructures 15.

The resist films 12E and 14B are then removed, thereby obtaining thethird exemplary sheet-like connector 10 shown in FIG. 28.

According to such a third exemplary sheet-like connector, the sameeffects as in the first exemplary sheet-like connector are achieved.

FIG. 40 is a cross-sectional view illustrating the construction of afourth exemplary sheet-like connector according to the presentinvention.

The fourth exemplary sheet-like connector 10 has the same constructionas that of the second sheet-like connector except that the electrodestructures 15 each has a columnar front-surface electrode part 16, andcan be produced in the same manner as the production process of thesecond sheet-like connector except that the conductors for front-surfaceelectrode parts are provided as the front-surface electrode parts 16without conducting an electrolytic etching treatment to the conductorsfor front-surface electrode parts as they are.

According the fourth sheet-like connector, the same effects as in thefirst exemplary sheet-like connector are achieved.

[Probe for Circuit Inspection and Inspection Apparatus for CircuitDevice]

FIG. 41 is a cross-sectional view illustrating the construction of anexemplary inspection apparatus for circuit devices according to thepresent invention. This inspection apparatus for circuit devices issuitable for respectively conducting electrical inspection of aplurality of integrated circuits formed on a wafer in a state of thewafer.

This inspection apparatus for circuit devices has a probe 1 for circuitinspection for conducting electrical connection between respectiveelectrodes 7 to be inspected of a wafer 6, which is a circuit device tobe inspected, and a tester. As illustrated on an enlarged scale in FIG.42 also, this probe 1 for circuit inspection has a circuit board 20 forinspection, on the front surface (lower surface in the drawing) of whicha plurality of inspection electrodes 21 have been formed in accordancewith a pattern according to a pattern of the electrodes 7 to beinspected in all integrated circuits formed on the wafer 6. Ananisotropically conductive connector 30 is arranged on the front surfaceof the circuit board 20 for inspection, and the sheet-like connector 10of the construction shown in FIG. 1, in which a plurality of theelectrode structures 15 have been arranged in accordance with thepattern according to the pattern of the electrodes 7 to be inspected inall the integrated circuits formed on the wafer 6, is arranged on afront surface (lower surface in the drawing) of the anisotropicallyconductive connector 30.

On a back surface (upper surface in the drawing) of the circuit board 20for inspection in the probe 1 for circuit inspection, is provided apressurizing plate 3 for pressurizing the probe 1 for circuit inspectiondownward. A wafer-mounting table 4, on which the wafer 6 is mounted, isprovided below the probe 1 for circuit inspection. A heater 5 isconnected to both pressurizing plate 3 and wafer-mounting table 4.

As a material for forming the circuit board 20 for inspection, may beused any of conventionally known various materials for boards, andspecific examples thereof include composite resin materials such asglass fiber-reinforced epoxy resins, glass fiber-reinforced phenolresins, glass fiber-reinforced polyimide resins and glassfiber-reinforced bismaleimide triazine resins, and ceramic materialssuch as glass, silicon dioxide and alumina.

When an inspection apparatus for conducting a WLBI test is constructed,that having a coefficient of linear thermal expansion of preferably atmost 3×10⁻⁵/K, more preferably 1×10⁻⁷ to 1×10⁻⁵/K, particularlypreferably 1×10⁻⁶ to 6×10⁻⁶/K is used.

Specific examples of such a board material include Pyrex (trademark)glass, quartz glass, alumina, beryllia, silicon carbide, aluminumnitride and boron nitride.

The anisotropically conductive connector 30 is formed by a frame plate31, in which a plurality of openings 32 have been formed correspondinglyto electrode regions, in which electrodes to be inspected in the wholeof the integrated circuits formed on the wafer, which is a circuitdevice to be inspected, have been arranged, and a plurality ofanisotropically conductive sheets 35 arranged so as to close therespective openings in the frame plate 31 and fixed to and supported byrespective opening edges of the frame plate 31.

No particular limitation is imposed on a material for forming the frameplate 31 so far as it has such stiffness as the resulting frame plate 31is hard to be deformed, and the shape thereof is stably retained. Forexample, various kinds of materials such as metallic materials, ceramicmaterials and resin materials may be used. When the frame plate 31 isformed by, for example, a metallic material, an insulating film may beformed on the surface of the frame plate 31.

Specific examples of the metallic material for forming the frame plate31 include metals such as iron, copper, nickel, chromium, cobalt,magnesium, manganese, molybdenum, indium, lead, palladium, titanium,tungsten, aluminum, gold, platinum and silver, and alloys or alloysteels composed of a combination of at least two of these metals.

Specific examples of the resin material forming the frame plate 31include liquid crystal polymers and polyimide resins.

When The inspection apparatus is that for conducting a WLBI (wafer levelburn-in) test, the material for forming the frame plate 31 preferablyhas a coefficient of linear thermal expansion of at most 3×10⁻⁵/K, morepreferably −1×10⁻⁷ to 1×10⁻⁵/K, particularly preferably 1×10⁻⁶ to8×10⁻⁶/K.

Specific examples of such a material include alloys or alloy steels ofmagnetic metals, such as invar alloys such as invar, Elinvar alloys suchas Elinvar, superinvar, covar and 42 alloy.

No particular limitation is imposed on the thickness of the frame plate31 so far as the shape thereof is retained, and the anisotropicallyconductive sheet 35 can be supported. Although the specific thicknessthereof varies depending on the material, it is preferably, for example,45 to 600 μm, more preferably 40 to 400 μm.

Each of the anisotropically conductive sheets 35 is formed by an elasticpolymeric substance and composed of a plurality of conductive parts 36formed in accordance with a pattern corresponding to a pattern ofelectrodes 7 to be inspected in an electrode region formed on the wafer6, which is a circuit board to be inspected, and each extending in athickness-wise direction of the sheet, and insulating parts 37 mutuallyinsulating these respective conductive parts 36. In the illustratedembodiment, projected portions 38 protruding from other surfaces thanportions, at which the conductive parts 36 and peripheral portionsthereof are located, are formed at those portions on both sides of theanisotropically conductive sheet 35.

In the respective conductive parts 36 in the anisotropically conductivesheet 35, conductive particles P exhibiting magnetism are contained at ahigh density in a state oriented so as to align in the thickness-wisedirection. On the other hand, the insulating parts 37 do not contain theconductive particles P at all or scarcely contain them.

The overall thickness (thickness of the conductive part 36 in theillustrated embodiment) of the anisotropically conductive sheet 35 ispreferably 50 to 2,000 μm, more preferably 70 to 1,000 μm, particularlypreferably 80 to 500 μm. When this thickness is 50 μm or greater,sufficient strength is imparted to such an anisotropically conductivesheet 35. When this thickness is 2,000 μm or smaller on the other hand,conductive parts 36 having necessary conductive properties are providedwith certainty.

The projected height of the projected portion 38 is preferably at least10% in total of the thickness of the projected portion 38, morepreferably at least 15%. Projected portions 38 having such a projectedheight are formed, whereby the conductive parts 36 are sufficientlycompressed by small pressing force, so that good conductivity is surelyachieved.

The projected height of the projected portion 38 is preferably at most100%, more preferably at most 70% of the shortest width or diameter ofthe projected portion 38. Projected portions 38 having such a projectedheight are formed, whereby the projected portions 38 are not buckledwhen they are pressurized, so that the prescribed conductivity is surelyachieved.

The elastic polymeric substance forming the anisotropically conductivesheet 35 is preferably a heat-resistant polymeric substance having acrosslinked structure. As curable polymeric substance-forming materialsusable for obtaining such a crosslinked polymeric substance, variousmaterials may be used. However, liquid silicone rubber is preferred.

The liquid silicone rubber may be any of addition type and condensationtype. However, addition type liquid silicone rubber is preferred. Thisaddition type liquid silicone rubber is that cured by a reaction of avinyl group with an Si—H bond and includes a one-pack type(one-component type) composed of polysiloxane having both vinyl groupand Si—H bond and a two-pack type (two-component type) composed ofpolysiloxane having a vinyl group and polysiloxane having an Si—H bond.In the present invention, addition type liquid silicone rubber of thetwo-pack type is preferably used.

When the anisotropically conductive sheet 35 is formed by a curedproduct (hereinafter referred to as “cured silicon rubber”) of theliquid silicone rubber, the cured silicone rubber preferably has acompression set of at most 10%, more preferably at most 8%, still morepreferably at most 6% at 150° C. If the compression set exceeds 10%, theconductive parts 36 tend to cause permanent set when the resultinganisotropically conductive connector is used repeatedly over many timesor used repeatedly under high-temperature environment, whereby chains ofthe conductive particles P in the conductive parts 36 are disordered. Asa result, it is difficult to retain the necessary conductivity.

In the present invention, the compression set of the cured siliconerubber can be measured by a method in accordance with JIS K 6249.

The cured silicone rubber preferably has a durometer A hardness of 10 to60, more preferably 15 to 55, particularly preferably 20 to 50 at 23° C.

If the durometer A hardness is lower than 10, the insulating parts 37mutually insulating the conductive parts 36 are easily over-distortedwhen pressurized, and it may be difficult in some cases to retain thenecessary insulating property between the conductive parts 36. If thedurometer A hardness exceeds 60 on the other hand, pressurizing force bya considerably heavy load is required for giving proper distortion tothe conductive parts 36, so that the wafer, which is a circuit board tobe inspected, tends to cause great deformation or breakage.

Further, if that having a durometer A hardness outside the above rangeis used as the cured silicone rubber, the conductive parts 36 tend tocause permanent set when the resulting anisotropically conductiveconnector is used repeatedly-over many times, whereby chains of theconductive particles in the conductive parts 36 are disordered. As aresult, it is difficult to retain the necessary conductivity.

When an inspection apparatus for conducting a WLBI test is constructed,the cured silicone rubber for forming the anisotropically conductivesheet 35 preferably has a durometer A hardness of 25 to 40 at 23° C.

If that having a durometer A hardness outside the above range is used asthe cured silicone rubber, the conductive parts 36 tend to causepermanent set when the WLBI test is conducted repeatedly, whereby chainsof the conductive particles in the conductive parts 36 are disordered.As a result, it is difficult to retain the necessary conductivity.

In the present invention, the durometer A hardness of the cured siliconerubber can be measured by a method in accordance with JIS K 6249.

Further, the cured silicone rubber preferably has tear strength of atleast 8 kN/m, more preferably at least 10 kN/m, still more preferably atleast 15 kN/m, particularly preferably at least 20 kN/m at 23° C. If thetear strength is lower than 8 kN/m, the resulting anisotropicallyconductive sheet 35 tends to deteriorate durability when it is distortedin excess.

In the present invention, the tear strength of the cured silicone rubbercan be measured by a method in accordance with JIS K 6249.

In the present invention, a proper curing catalyst may be used forcuring the addition type liquid silicone rubber. As such a curingcatalyst, may be used a platinum-containing catalyst. Specific examplesthereof include publicly known catalysts such as platinic chloride andsalts thereof, platinum-unsaturated group-containing siloxane complexes,vinylsiloxane-platinum complexes,platinum-1,3-divinyltetramethyldisiloxane complexes, complexes oftriorganophosphine or phosphine and platinum, acetyl acetate platinumchelates, and cyclic diene-platinum complexes.

The amount of the curing catalyst used is suitably selected in view ofthe kind of the curing catalyst and other curing treatment conditions.However, it is generally 3 to 15 parts by weight per 100 parts by weightof the addition type liquid silicone rubber.

In order to, for example, improve the thixotropic property of theaddition type liquid silicone rubber, adjust the viscosity, improve thedispersion stability of the conductive particles or provide a basematerial having high strength, a general inorganic filler such as silicapowder, colloidal silica, aerogel silica or alumina may be contained inthe addition type liquid silicone rubber as needed.

As the conductive particles P contained in the conductive parts 36, maypreferably be used particles obtained by coating the surfaces of coreparticles (hereinafter also referred to as “magnetic core particles”)exhibiting magnetism with high-conductive metal.

The term “high-conductive metal” as used herein means a metal having aconductivity of at least 5×10⁶ Ω⁻¹m⁻¹ at 0° C.

The magnetic core particles for obtaining the conductive particles Ppreferably have a number average particle diameter of 3 to 40 μm.

The number average particle diameter of the magnetic core particlesmeans a value measured by a laser diffraction scattering method.

When the number average particle diameter is 3 μm or greater, conductiveparts 36 easy to be deformed under pressure, low in resistance value andhigh in connection reliability can be easily obtained. When the numberaverage particle diameter is 40 μm or smaller on the other hand, minuteconductive parts 36 can be easily formed, and the resultant conductiveparts 36 tend to have stable conductivity.

Further, the magnetic core particles preferably have a BET specificsurface area of 10 to 500 m²/kg, more preferably 20 to 500 m²/kg,particularly preferably 50 to 400 m²/kg.

When the BET specific surface area is 10 m²/kg or wider, such magneticcore particles can be surely plated in a required amount because an areacapable of being plated in the magnetic core particles is sufficientlywide. Accordingly, conductive particles P high in conductivity can beobtained, and stable and high conductivity is achieved because a contactarea between the conductive particles P is sufficiently wide. When theBET specific surface area is 500 m²/kg or smaller on the other hand,such magnetic core particles do not become brittle, so that they are notbroken when physical stress is applied, and stable and high conductivityis retained.

Further, the magnetic core particles preferably have a coefficient ofvariation of particle diameter of at most 50%, more preferably at most40%, still more preferably at most 30%, particularly preferably at most20%.

The coefficient of variation of particle diameter is a value determinedin accordance with the expression: (σ/Dn)×100, wherein σ is a standarddeviation value of the particle diameter, and Dn is a number averageparticle diameter of the particles.

When the coefficient of variation of particle diameter is 50% or lower,conductive parts 36 narrow in scatter of conductivity can be formedbecause the evenness of particle diameter is high.

As a material for forming the magnetic core particles, may be used iron,nickel, cobalt, a material obtained by coating such a metal with copperor a resin, or the like. Those having a saturation magnetization of atleast 0.1 Wb/m² may be preferably used. The saturation magnetizationthereof is more preferably at least 0.3 Wb/m², particularly preferablyat least 0.5 Wb/m². Specific examples of the material include iron,nickel, cobalt and alloys thereof.

As the high-conductive metal applied to the surfaces of the magneticcore particles, may be used gold, silver, rhodium, platinum, chromium orthe like. Among these, gold is preferably used in that it is chemicallystable and has a high electric conductivity.

In the conductive particles P, a proportion [(mass of high-conductivemetal/mass of core particles)×100] of the high-conductive metal to thecore particles is at least 15% by mass, preferably 25 to 35% by mass.

If the proportion of the high-conductive metal is lower than 15% bymass, the conductivity of such conductive particles P is markedlydeteriorated when the resulting anisotropically conductive connector isused repeatedly under high-temperature environment. As a result, thenecessary conductivity cannot be retained.

The BET specific surface area of the conductive particles P ispreferably 10 to 500 m²/kg.

When the BET specific surface area is 10 m²/kg or wider, the surfacearea of the coating layer becomes sufficiently great, so that thecoating layer great in the total weight of the high-conductive metal canbe formed. Accordingly, particles high in conductivity can be obtained.In addition, stable and high conductivity can be achieved because acontact area among the conductive particles P is sufficiently wide. Whenthe BET specific surface area is 500 m²/kg or smaller on the other hand,such conductive particles do not become brittle, and thus they are notbroken when physical stress is applied thereto, and the stable and highconductivity is retained.

The number average particle diameter of the conductive particles P ispreferably 3 to 40 μm, more preferably 6 to 25 μm.

When such conductive particles P are used, the resulting anisotropicallyconductive sheet 35 becomes easy to be deformed under pressure. Inaddition, sufficient electrical connection is achieved between theconductive particles P in the conductive parts 36.

No particular limitation is imposed on the shape of the conductiveparticles P. However, they are preferably in the shape of a sphere orstar, or a mass of secondary particles obtained by agglomerating theseparticles in that these particles can be easily dispersed in thepolymeric substance-forming material.

The content of water in the conductive particles P is preferably at most5% by mass, more preferably at most 3% by mass, further preferably atmost 2% by mass, particularly preferably at most 1% by mass. Bysatisfying such conditions, bubbling can be prevented or inhibited uponthe curing treatment in the formation of the anisotropically conductivesheet 35.

The conductive particles P may be those obtained by treating surfacesthereof with a coupling agent such as a silane coupling agent. Bytreating the surfaces of the conductive particles P with the couplingagent, the adhesion property of the conductive particles P to theelastic polymeric substance is improved. As a result, the resultinganisotropically conductive sheet 35 becomes high in durability uponrepeated use.

The amount of the coupling agent used is suitably selected within limitsnot affecting the conductivity of the conductive particles P. However,it is preferably such an amount that a coating rate (proportion of anarea coated with the coupling agent to the surface area of theconductive particles) of the coupling agent on the surfaces of theconductive particles P amounts to at least 5%, more preferably 7 to100%, further preferably 10 to 100%, particularly preferably 20 to 100%.

Such conductive particles P may be obtained in accordance with, forexample, the following process.

Particles are first formed by commercial process from a ferromagneticmaterial, or commercially available particles of a ferromagneticsubstance are provided. The particles are subjected to a classifyingtreatment to prepare magnetic core particles having a required particlediameter.

The classification treatment of the particles can be conducted by meansof, for example, a classifier such as an air classifier or sonicclassifier.

Specific conditions for the classification treatment are suitably presetaccording to the intended number average particle diameter of themagnetic core particles, the kind of the classifier, and the like.

Surfaces of the magnetic core particles are then treated with an acidand further washed with, for example, purified water, thereby removingimpurities such as dirt, foreign matter and oxidized films present onthe surfaces of the magnetic core particles. Thereafter, the surfaces ofthe magnetic core particles are coated with a high-conductive metal,thereby obtaining conductive particles.

As examples of the acid used for treating the surfaces of the magneticcore particles, may be mentioned hydrochloric acid.

As a method for coating the surfaces of the magnetic core particles withthe high-conductive metal, may be used electroless plating, displacementplating or the like. However, the method is not limited to thesemethods.

A process for producing the conductive particles by the electrolessplating or displacement plating will be described. The magnetic coreparticles subjected to the acid treatment and washing treatment arefirst added to a plating solution to prepare a slurry, and electrolessplating or displacement plating on the magnetic core particles isconducted while stirring the slurry. The particles in the slurry arethen separated from the plating solution. Thereafter, the particlesseparated are subjected to a washing treatment with, for example,purified water, thereby obtaining conductive particles with the surfacesof the magnetic core particles coated with the high-conductive metal.

Alternatively, primer plating may be conducted on the surfaces of themagnetic core particles to form a primer plating layer, and a platinglayer composed of the high-conductive metal may be then formed on thesurface of the primer plating layer. No particular limitation is imposedon the process for forming the primer plating layer and the platinglayer formed thereon. However, it is preferable to form the primerplating layer on the surfaces of the magnetic core particles by theelectroless plating and then form the plating layer composed of thehigh-conductive metal on the surface of the primer plating layer by thedisplacement plating.

No particular limitation is imposed on the plating solution used in theelectroless plating or displacement plating, and various kinds ofcommercially available plating solutions may be used.

Since conductive particles having a great particle diameter may beproduced due to aggregation of the magnetic core particles upon thecoating of the surfaces of the magnetic core particles with thehigh-conductive metal, the resulting conductive particles are preferablyclassified as needed. By conducting the classification treatment, theconductive particles having the expected particle diameter can be surelyobtained.

As examples of a classifier used for conducting the classificationtreatment of the conductive particles, may be mentioned thoseexemplified as the classifier used in the classification treatment ofthe magnetic core particles.

The proportion of the conductive particles P contained in the conductiveparts 36 is preferably 10 to 60%, more preferably 15 to 50% in terms ofvolume fraction. If this proportion is lower than 10%, conductive parts36 sufficiently low in electric resistance value may not be obtained insome cases. If the proportion exceeds 60% on the other hand, theresulting conductive parts 36 are liable to be brittle, so thatelasticity required of the conductive parts 36 may not be achieved insome cases.

Such an anisotropically conductive connector as described above can beproduced in accordance with, for example, the process described inJapanese Patent Application Laid-Open No. 2002-324600.

In the above-described inspection apparatus, a wafer 6, which is anobject of inspection, is mounted on the wafer-mounting table 4, and theprobe 1 for circuit inspection is then pressurized downward by thepressurizing plate 3, whereby the respective front-surface electrodeparts 16 in the electrode structures 15 of the sheet-like connector 10thereof are brought into contact with their corresponding electrodes 7to be inspected of the wafer 6, and moreover the respective electrodes 7to be inspected of the wafer 6 are pressurized by the front-surfaceelectrodes parts 16. In this state, the conductive parts 36 in theanisotropically conductive sheets 35 of the anisotropically conductiveconnector 30 are respectively held and pressurized by the inspectionelectrodes 21 of the circuit board 20 for inspection and theback-surface electrode parts 17 in the electrode structures 15 of thesheet-like connector 10 and compressed in the thickness-wise directionof the anisotropically conductive sheets, whereby conductive paths areformed in the respective conductive parts 36 in the thickness-wisedirection thereof. As a result, electrical connection between theelectrodes 7 to be inspected of the wafer 6 and the inspectionelectrodes 21 of the circuit board 20 for inspection is achieved.Thereafter, the wafer 6 is heated to a prescribed temperature by theheater 5 through the wafer-mounting table 4 and pressurizing plate 3. Inthis state, necessary electrical inspection is curried out on each of aplurality of integrated circuits on the wafer 6.

According to the above-described probe for circuit inspection, thesheet-like connector 10 shown in FIG. 1 is provided, so that a stableelectrically connected state can be surely achieved even to a wafer 6,on which electrodes 7 to be inspected have been formed at a small pitch.In addition, since the electrode structures 15 in the sheet-likeconnector 10 are prevented from falling off, high durability isachieved.

According to the inspection apparatus described above, the probe 1 forcircuit inspection having the sheet-like connector 10 shown in FIG. 1 isprovided, so that a stable electrically connected state can be surelyachieved even to a wafer 6, on which electrodes 7 to be inspected havebeen formed at a small pitch. In addition, inspection can be performedwith high reliability over a long period of time even when theinspection is conducted as to a great number of wafers, since the probe1 for circuit inspection have high durability.

The inspection apparatus for circuit devices according to the presentinvention is not limited to the above-described embodiments, and variouschanges or modifications may be added thereto as described below.

(1) The probe 1 for circuit inspection shown in FIGS. 41 and 42 isintended to achieve electrical connection collectively as to electrodes7 to be inspected of all integrated circuits formed on a wafer 6.However, it may be intended to achieve electrical connection as toelectrodes 7 to be inspected of a plurality of integrated circuitsselected from among all the integrated circuits formed on the wafer 6.The number of integrated circuits selected is suitably selected in viewof the size of the wafer 6, the number of integrated circuits formed onthe wafer 6, the number of electrodes to be inspected in each integratedcircuit, and the like. However, the number is, for example, 16, 32, 64or 128.

In the inspection apparatus having such a probe for circuit inspection,the probe for circuit inspection is electrically connected to electrodes7 to be inspected of a plurality of integrated circuits selected fromamong all the integrated circuits formed on the wafer 6 to conductinspection. Thereafter, the probe for circuit inspection is electricallyconnected to electrodes 7 to be inspected of a plurality of integratedcircuits selected from among other integrated circuits to conductinspection. This process is repeated, whereby electrical inspection ofall the integrated circuits formed on the wafer 6 can be conducted.

According to such an inspection apparatus, the numbers of inspectionelectrodes and wires in a circuit board for inspection used can belessened compared with a method of collectively conducting inspection asto all integrated circuits in the case where electrical inspection isconducted as to integrated circuits formed in a high degree ofintegration on a wafer having a diameter of 8 or 12 inches, wherebyproduction cost of the inspection apparatus can be reduced.

(2) In addition to the conductive parts 36 formed in accordance with thepattern corresponding to the pattern of the electrodes 7 to beinspected, conductive parts for non-connection that are not electricallyconnected to any electrode 7 to be inspected may be formed in theanisotropically conductive sheets 35 in the anisotropically conductiveconnector 30.

(3) The circuit device, which is an object of inspection by theinspection apparatus according to the present invention, is not limitedto the wafer, on which a great number of integrated circuits have beenformed, and the inspection apparatus may be constructed as an inspectionapparatus for circuits formed in a semiconductor chip, a packaged LSIsuch as BGA and CSP, a semiconductor integrated circuit device such asCMC, or the like.

EXAMPLES

The present invention will hereinafter be described specifically by thefollowing examples. However, the present invention is not limited tothese examples.

[Production of Wafer for Test]

As illustrated in FIG. 44, 596 square integrated circuits L in total,which each had dimensions of 6.5 mm×6.5 mm, were formed on a wafer 6made of silicon (coefficient of linear thermal expansion: 3.3×10⁻⁶/K)and having a diameter of 8 inches. Each of the integrated circuits Lformed on the wafer 6 has a region A of electrodes to be inspected atits center as illustrated in FIG. 45. In the region A of the electrodesto be inspected, 26 rectangular electrodes 7 to be inspected each havingdimensions of 200 μm in a vertical direction (upper and lower directionin FIG. 46) and 80 μm in a lateral direction (left and right directionin FIG. 46) are arranged at a pitch of 120 μm in 2 lines (the number ofelectrodes 7 to be inspected in one line: 13) in the lateral direction.A clearance between electrodes 7 to be inspected adjoining in thevertical direction is 450 μm. Every 2 electrodes of the 26 electrodes 7to be inspected are electrically connected to each other. The totalnumber of the electrodes 7 to be inspected on the whole wafer 6 is15,496. This wafer will hereinafter be referred to as “Wafer W1 fortest”.

Example 1

[Production of Sheet-Like Connectors M(1-1) to M(1-5)]:

A laminated polyimide sheet with copper layers each having a thicknessof 5 μm laminated on both sides of a polyimide sheet having a thicknessof 12.5 μm and a laminated thermoplastic polyimide sheet with a copperlayer having a thickness of 5 μm laminated on one side of athermoplastic polyimide sheet were provided, they were arranged in sucha manner that a surface of the laminated thermoplastic polyimide sheet,on which no copper layer was not laminated, faces the surface of onecopper layer of the laminated polyimide sheet, and both sheets weresubjected to a pressure-bonding treatment under heat, thereby producinga laminate material (10A) of the construction shown in FIG. 3.

The resultant laminated material (10A) is such that a first frontsurface-side metal layer (19A) composed of copper and having a thicknessof 5 μm, an insulating layer (16B) composed of polyimide and having athickness of 25 μm and a second front surface-side metal layer (16A)composed of copper and having a thickness of 5 μm are laminated on afront surface of an insulating sheet (11) composed of polyimide andhaving a thickness of 12.5 μm in this order, and a back surface-sidemetal layer (17A) composed of copper and having a thickness of 5 μm islaminated on a back surface of the insulating sheet (11).

To the laminate material (10A), a resist film (12A) was formed on thewhole surface of the second front surface-side metal layer (16A) by adry film resist having a thickness of 25 μm, and a resist film (13), inwhich 15,496 patterned circular holes (13K) having a diameter of 60 μmhad been formed in accordance with a pattern corresponding to a patternof the electrodes to be inspected formed on Wafer W1 for test, wasformed on the surface of the back surface-side metal layer (17A) (seeFIG. 4). In the formation of the resist film (13), an exposure treatmentwas conducted by irradiation of ultraviolet light of 80 mJ by ahigh-pressure mercury lamp, and a development treatment was conducted byrepeating a process of immersing the laminate material for 40 seconds ina developer composed of a 1% aqueous solution of sodium hydroxide twice.

The back surface-side metal layer (17A) was then subjected to an etchingtreatment with a ferric chloride etchant under conditions of 50° C. for30 seconds, thereby forming, in the back surface-side metal layer (17A),15,496 through-holes (17H) linked to the respective patterned holes(13K) in the resist film (13) (see FIG. 5). Thereafter, the insulatingsheet (11) was subjected to an etching treatment with a hydrazineetchant under conditions of 60° C. for 120 minutes, thereby forming, inthe insulating sheet (11), 15,496 through-holes (11H) linked to therespective through-holes (17K) in the back surface-side metal layer(17A) (see FIG. 6). Each of the through-holes (11H) was in a taperedform that the diameter becomes gradually small from the back surface ofthe insulating sheet (11) toward the front surface thereof, an openingdiameter on the back surface side was 60 μm, and an opening diameter onthe front surface side was 45 μm.

Thereafter, the first front surface-side metal layer (19A) was subjectedto an etching treatment with a ferric chloride etchant under conditionsof 50° C. for 30 seconds, thereby forming, in the first frontsurface-side metal layer (19A), 15,496 through-holes (19H) linked to therespective through-holes (11K) in the insulating sheet (11) (see FIG.7). Further, the insulating layer (16B) was subjected to an etchingtreatment with a hydrazine etchant under conditions of 60° C. for 120minutes, thereby forming, in the insulating layer (16B), 15,496through-holes 16H linked to the respective through-holes (19H) in thefirst front surface-side metal layer (19A) (see FIG. 8). Each of thethrough-holes (16H) was in a tapered form that the diameter becomesgradually small from the back surface of the insulating layer (16B)toward the front surface thereof, an opening diameter on the backsurface side was 45 μm, and an opening diameter on the front surfaceside was 17 μm.

In such a manner, 15,496 recesses (10K) for forming electrode structureswith the respective through-holes (17H) in the back surface-side metallayer (17A), the respective through-holes (11H) in the insulating sheet(11) the respective through-holes (19H) in the first front surface-sidemetal layer (19A) and the respective through-holes (16H) in theinsulating layer (16B) linked to one another were formed in the backsurface of the laminate material (10A).

After the resist films (12A and 13) were removed from the laminatematerial (10A), in which the recesses (10K) for forming electrodestructures had been formed, by immersing the laminate material (10A) for2 minutes in a sodium hydroxide solution at 45° C., a resist film (12B)was formed with a dry film resist having a thickness of 25 μm on thelaminate material (10A) so as to cover the whole surface of the secondfront surface-side metal layer (16A) and a resist film (14A), in which15,496 patterned rectangular holes (14K) having dimensions of 150 μm×60μm and linked to the respective through-holes (17H) in the backsurface-side metal layer (17A) had been formed, was formed on thesurface of the back surface-side metal layer (17A) (see FIG. 9). In theformation of the resist film (14A), an exposure treatment was conductedby irradiation of ultraviolet light of 80 mJ by a high-pressure mercurylamp, and a development treatment was conducted by repeating a processof immersing the laminate material for 40 seconds in a developercomposed of a 1% aqueous solution of sodium hydroxide twice.

The laminate material (10A) was then immersed in a plating bathcontaining nickel sulfamate to subject the laminate material (10A) to anelectroplating treatment by using the second front surface-side metallayer (16A) as an electrode to fill a metal into the respective recesses(10K) for forming electrode structures and the respective patternedholes (14K) in the resist film (14A), thereby forming back-surfaceelectrode parts (17) linked to one another through front-surfaceelectrode parts (16), short circuit parts (18) and the back surface-sidemetal layer (17A) (see FIG. 10).

After the laminate material (10A), in which the front-surface electrodeparts (16), short circuit parts (18) and back-surface electrode parts(17) had been formed in such a manner, was immersed for 2 minutes in asodium hydroxide solution at 45° C. to remove the resist films (12B and14A) from the laminate material (10A), a patterned resist film (14B) foretching was formed with a dry film resist having a thickness of 25 μm soas to cover the back-surface electrode parts (17) (see FIG. 11). In theformation of the resist film (14B), an exposure treatment was conductedby irradiation of ultraviolet light of 80 mJ by a high-pressure mercurylamp, and a development treatment was conducted by repeating a processof immersing the laminate material for 40 seconds in a developercomposed of a 1% aqueous solution of sodium hydroxide twice. Thereafter,the second front surface-side metal layer (16A) and the backsurface-side metal layer (17A) were subjected to an etching treatmentwith an ammonia etchant under conditions of 50° C. for 30 seconds,thereby removing the whole of the second front surface-side metal layer(16A) and moreover exposed portions of the back surface-side metal layer(17A) to separate the back-surface electrode parts (17) from one another(see FIG. 12).

The insulating layer (16B) was then subjected to an etching treatmentwith a hydrazine etchant under conditions of 60° C. for 120 minutes toremove the insulating layer (16B) and moreover the resist film (14B),thereby exposing the front-surface electrode parts (16), first frontsurface-side metal layer (19A) and back-surface electrode parts (17)(see FIG. 13). Thereafter, a patterned resist film (12C) was formed witha dry film resist having 25 μm so as to cover the front-surfaceelectrode parts (16) and portions to become holding parts (19) in thefirst front surface-side metal layer (19A), and a resist film (14C) wasformed so as to cover the back surface of the insulating sheet (11) andall of the back-surface electrode parts (17) (see FIG. 14). In theformation of the resist film (12C), an exposure treatment was conductedby irradiation of ultraviolet light of 80 mJ by a high-pressure mercurylamp, and a development treatment was conducted by repeating a processof immersing the laminate material for 40 seconds in a developercomposed of a 1% aqueous solution of sodium hydroxide twice. The firstfront surface-side metal layer (19A) was then subjected to an etchingtreatment with a ferric chloride etchant under conditions of 50° C. for30 seconds, thereby forming disc ring-like holding parts (19) eachcontinuously extending from a peripheral surface of a base end portionof the front-surface electrode part (16) outward and radially along thefront surface of the insulating sheet (11), thus resulting in theformation of the electrode structures (15) (see FIG. 15).

The resist films (12C) was then removed from the front-surface electrodeparts (16) and holding parts (19) and the resist film (14C) was removedfrom the back surface of the insulating sheet (11) and the back-surfaceelectrode parts (17), thereby producing a sheet-like connector (10)according to the present invention (see FIG. 1).

The sheet-like connector (10) thus obtained is such that the thickness dof the insulating sheet (11) is 12.5 μm, the shape of the front-surfaceelectrode part (16) in each of the electrode structures (15) is atruncated cone shape, the diameter R₁ of a base end thereof is 45 μm,the diameter R₂ of a tip end thereof is 17 μm, the projected height hthereof is 25 μm, the shape of the short circuit part (18) is atruncated cone shape, the diameter R₃ of one end on the front surfaceside thereof is 45 μm, the diameter R₄ of the other end on the backsurface side is 60 μm, the shape of the back-surface electrode part (17)is a rectangular flat plate shape, the width (diameter R₅) thereof is 60μm, the length thereof is 150 μm, the thickness D₂ is 30 μm, the shapeof the holding part (19) is a circular ring plate form, the outerdiameter R₆ thereof is 50 μm, and the thickness D₁ thereof is 5 μm.

In such a manner, 5 sheet-like connectors in total were produced. Thesesheet-like connectors are referred to as “Sheet-like Connector M(1-1)”to “Sheet-like Connector M(1-5)”.

[Production of Anisotropically Conductive Connector]

(1) Preparation of Magnetic Core Particles:

Commercially available nickel particles (product of Westaim Co.,“FC1000”) were used to prepare magnetic core particles in the followingmanner.

An air classifier “Turboclassifier TC-15N” manufactured by NisshinEngineering Co., Ltd. was used to classify 2 kg of nickel particlesunder conditions of a specific gravity of 8.9, an air flow of 2.5m³/min, a rotor speed of 1,600 rpm, a classification point of 25 μm anda feed rate of nickel particles of 16 g/min, thereby collecting 1.8 kgof nickel particles, and 1.8 kg of these nickel particles were furtherclassified under conditions of a specific gravity of 8.9, an air flow of2.5 m³/min, a rotor speed of 3,000 rpm, a classification point of 10 μmand a feed rate of nickel particles of 14 g/min to collect 1.5 kg ofnickel particles.

A sonic sifter “SW-20AT Model” manufactured by Tsutsui Rikagaku KikiK.K. was then used to further classify 120 g of the nickel particlesclassified by the air classifier. Specifically, 4 sieves each having adiameter of 200 mm and respectively having opening diameters of 25 μm,20 μm, 16 μm and 8 μm were superimposed on one another in this orderfrom above. Each of the sieves was charged with 10 g of ceramic ballshaving a diameter of 2 mm, and 20 g of the nickel particles were placedon the uppermost sieve (opening diameter: 25 μm) to classify them underconditions of 55 Hz for 12 minutes and 125 Hz for 15 minutes, therebycollecting nickel particles captured on the lowest sieve (openingdiameter: 8 μm). This process was conducted repeatedly 25 times intotal, thereby preparing 110 g of magnetic core particles.

The magnetic core particles thus obtained had a number average particlediameter of 10 μm, a coefficient of variation of particle diameter of10%, a BET specific surface area of 0.2×10³ m²/kg and a saturationmagnetization of 0.6 Wb/m².

The magnetic core particles are referred to as “Magnetic Core Particles[A]”.

[2] Preparation of Conductive Particles:

Into a treating vessel of a powder plating apparatus, were poured 100 gof Magnetic Core Particles [A], and 2 L of 0.32N hydrochloric acid werefurther added. The resultant mixture was stirred to obtain a slurrycontaining Magnetic Core Particles [A]. This slurry was stirred atordinary temperature for 30 minutes, thereby conducting an acidtreatment for Magnetic Core Particles [A]. Thereafter, the slurry thustreated was left at rest for 1 minute to precipitate Magnetic CoreParticles [A], and a supernatant was removed.

To the Magnetic Core Particles [A] subjected to the acid treatment, wereadded 2 L of purified water, and the mixture was stirred at ordinarytemperature for 2 minutes. The mixture was further then left at rest for1 minute to precipitate Magnetic Core Particles [A], and a supernatantwas removed. This process was further conducted repeatedly twice,thereby conducting a washing treatment for Magnetic Core Particles [A].

To the Magnetic Core Particles [A] subjected to the acid treatment andwashing treatment, were added 2 L of a gold plating solution containinggold in a proportion of 20 g/L. The temperature of the treating vesselwas raised to 90° C. and the contents were stirred, thereby preparing aslurry. While stirring the slurry in this state, Magnetic Core Particles[A] were subjected to displacement plating with gold. Thereafter, theslurry was left at rest while allowing it to cool, thereby precipitatingparticles, and a supernatant was removed to prepare conductiveparticles.

To the conductive particles obtained in such a manner, were added 2 L ofpurified water, and the mixture was stirred at ordinary temperature for2 minutes. Thereafter, the mixture was left at rest for 1 minute toprecipitate conductive particles, and a supernatant was removed. Thisprocess was conducted repeatedly further twice, and 2 L of purifiedwater heated to 90° C. were then added to the particles, and the mixturewas stirred. The resultant slurry was filtered through filter paper tocollect conductive particles. The conductive particles thus obtainedwere dried in a dryer set to 90° C.

The resultant conductive particles had a number average particlediameter of 12 μm and a BET specific surface area of 0.15×10³ m²/kg, anda value of (mass of gold forming a coating layer/total mass of theconductive particles) was 0.3.

The conductive particles are referred to as “Conductive Particles (a)”.

(3) Production of Frame Plate:

A frame plate (31) having a diameter of 8 inches and 596 openings (32)formed corresponding to the respective regions of the electrodes to beinspected in Wafer W1 for test described above was produced under thefollowing conditions in accordance with the construction shown in FIGS.47 and 48.

A material of this frame plate (31) is covar (coefficient of linearthermal expansion: 5×10⁻⁶/K), and the thickness thereof is 60 μm.

The openings (32) each have dimensions of 1,800 μm in a lateraldirection (left and right direction in FIGS. 47 and 48) and 600 μm in avertical direction (upper and lower direction in FIGS. 47 and 48).

An air inflow hole (33) is formed at a central position between openings(32) adjoining in the vertical direction, and the diameter thereof is1,000 μm.

(4) Preparation of Molding Material for Anisotropically ConductiveSheet:

To 100 parts by weight of addition type liquid silicone rubber, wereadded 30 parts by weight of Conductive Particles [a] to mix them.Thereafter, the resultant mixture was subjected to a defoaming treatmentby pressure reduction, thereby preparing a molding material foranisotropically conductive sheet.

In the above-described process, the addition type liquid silicone rubberused is of a two-pack type composed of Liquid A and Liquid B each havinga viscosity of 250 Pa·s. The cured product thereof has a compression setof 5%, a durometer A hardness of 32 and tear strength of 25 kN/m.

Properties of the addition type liquid silicone rubber and cured productthereof were measured in the following manner.

-   (i) The viscosity of the addition type liquid silicone rubber was a    value measured by means of a Brookfield type viscometer at 23±2° C.-   (ii) The compression set of the cured silicone rubber was measured    in the following manner.

Liquid A and Liquid B in the two-pack type liquid silicone rubber werestirred and mixed in proportions that their amounts become equal. Afterthe mixture was then poured into a mold and subjected to a defoamingtreatment by pressure reduction, it was subjected to a curing treatmentunder conditions of 120° C. for 30 minutes, thereby forming a columnarbody composed of a cured product of the silicone rubber and having athickness of 12.7 mm and a diameter of 29 mm. This columnar body waspost-cured under conditions of 200° C. for 4 hours. The columnar bodyobtained in such a manner was used as a specimen to measure acompression set at 150±2° C. in accordance with JIS K 6249.

-   (iii) The tear strength of the cured silicone rubber was measured in    the following manner.

The curing treatment and post-curing of the addition type liquidsilicone rubber were conducted under the same conditions as those in theitem (ii) to form a sheet having a thickness of 2.5 mm. A crescent typespecimen was produced by punching from this sheet to measure its tearstrength at 23±2° C. in accordance with JIS K 6249.

(iv) The durometer A hardness was determined by using, as a specimen, alaminate obtained by stacking 5 sheets produced in the same manner as inthe item (iii) on one another, and measuring a value at 23±2° C. inaccordance with JIS K 6249.

(5) Production of Anisotropically Conductive Connector:

The frame plate (31) produced in the item (1) and the molding materialprepared in the item (4) were used to form 596 anisotropicallyconductive sheets (35) of the construction shown in FIG. 42, which werearranged so as to close the respective openings in the frame plate (31)and fixed to and supported by respective opening edges of the frameplate (31), in accordance with the process described in Japanese PatentApplication Laid-Open No. 2002-324600, thereby producing ananisotropically conductive connector. The curing treatment of themolding material layers was conducted under conditions of 100° C. for 1hour while applying a magnetic field of 2 T by electromagnets.

The resultant anisotropically conductive sheets (35) will be describedspecifically. Each of the anisotropically conductive sheets (35) hasdimensions of 2,500 μm in a lateral direction and 1,400 μm in a verticaldirection, and 26 conductive parts (36) are arranged at a pitch of 120μm in 2 lines (the number of conductive parts in one line: 13; clearancebetween conductive parts adjoining in the vertical direction: 450 μm) inthe lateral direction. With respect to each of the conductive parts(36), its dimensions are 60 μm in the lateral direction and 200 μm inthe vertical direction, the thickness is 150 μm, the projected height ofthe projected portion (38) is 25 μm, and the thickness of the insulatingpart (37) is 100 μm. Conductive parts for non-connection are arrangedbetween the conductive part (36) located most outside in the lateraldirection and the opening edge of the frame plate. Each of theconductive parts for non-connection has dimensions of 80 μm in thelateral direction and 300 μm in the vertical direction and a thicknessof 150 μm.

The content of the conductive particles in the conductive parts (36) ineach of the anisotropically conductive sheets (35) was investigated. Asa result, the content was about 30% in terms of a volume fraction in allthe conductive parts (36).

The resultant anisotropically conductive connector is referred to as“Anisotropically Conductive Connector C1”.

(6) Production of Circuit Board for Inspection:

Alumina ceramic (coefficient of linear thermal expansion: 4.8×10⁻⁶/K)was used as a board material to produce a circuit board (20) forinspection, in which inspection electrodes (21) had been formed inaccordance with a pattern corresponding to the pattern of the electrodesto be inspected in Wafer W1 for test. This circuit board (20) forinspection has dimensions of 30 cm×30 cm as a whole and is rectangular.The inspection electrodes thereof each have dimensions of 60 μm in thelateral direction and 200 μm in the vertical direction. The resultantcircuit board for inspection is referred to as “Circuit Board T1 forinspection”.

(7) Connection Stability Test:

Sheet-like Connector M(1-1) to Sheet-Like Connector M(1-5) wererespectively subjected to a connection stability test in the followingmanner.

Wafer W1 for test was arranged on a test table, a sheet-like connectorwas arranged on the surface of Wafer W1 for test in alignment in such amanner that the respective front-surface electrode parts thereof arelocated on electrodes to be inspected of Wafer W1 for test, andAnisotropically Conductive Connector C1 was arranged on this sheet-likeconnector in alignment in such a manner that the respective conductiveparts thereof are located on the back-surface electrode parts of thesheet-like connector. Circuit Board T1 for inspection was arranged onthis anisotropically conductive connector in alignment in such a mannerthat the respective inspection electrodes thereof are located on theconductive parts of the anisotropically conductive connector. Further,Circuit Board T1 for inspection was pressurized downward under a load of12.4 kg (load applied to every conductive part of the anisotropicallyconductive connector: 0.8 g on the average).

With respect to 15,496 inspection electrodes in Circuit Board T1 fortest, an electric resistance between every two inspection electrodeselectrically connected to each other through Anisotropically ConductiveConnector C1, the sheet-like connector and Wafer W1 for test wasmeasured successively at room temperature (25° C.), and a half value ofthe electric resistance value measured was recorded as an electricresistance (hereinafter referred to as “conduction resistance”) betweenan inspection electrode of Circuit Board T1 for inspection and anelectrode to be inspected of Wafer W1 for test to find a proportion ofmeasuring points, at which the conduction resistance was lower than 1 Ω,to all measuring points.

Further, a proportion of measuring points, at which the conductionresistance was lower than 1 Ω, to all measuring points was found in thesame manner as described above except that the load applied to CircuitBoard T1 for inspection was changed from 12.4 kg to 31 kg (load appliedto every conductive part of the anisotropically conductive connector: 2g on the average).

The results are shown in Table 1.

(8) Durability Test:

Sheet-like Connector M(1-1), Sheet-like Connector M(1-2) and Sheet-likeConnector M(1-4) were respectively subjected to a durability test in thefollowing manner.

Wafer W1 for test was arranged on a test table equipped with an electricheater, a sheet-like connector was arranged on the surface of Wafer W1for test in alignment in such a manner that the respective front-surfaceelectrode parts thereof are located on electrodes to be inspected ofWafer W1 for test, and Anisotropically Conductive Connector C1 wasarranged on this sheet-like connector in alignment in such a manner thatthe respective conductive parts thereof are located on the back-surfaceelectrode parts of the sheet-like connector. Circuit Board T1 forinspection was arranged on this anisotropically conductive connector inalignment in such a manner that the respective inspection electrodesthereof are located on the conductive parts of the anisotropicallyconductive connector. Further, Circuit Board T1 for inspection waspressurized downward under a load of 31 kg (load applied to everyconductive part of the anisotropically conductive connector: 2 g on theaverage). After the test table was then heated to 85° C., and thetemperature of the test table became stable, an electric resistancebetween every two inspection electrodes electrically connected to eachother through Anisotropically Conductive Connector C1, the sheet-likeconnector and Wafer W1 for test among 15,496 inspection electrodes inCircuit Board T1 for inspection was measured successively, and a halfvalue of the electric resistance value measured was recorded as anelectric resistance (hereinafter referred to as “conduction resistance”)between an inspection electrode of Circuit Board T1 for inspection andan electrode to be inspected of Wafer W1 for test to count the number ofmeasuring points, at which the conduction resistance was 1 Ω or higher.After retained for 30 seconds in this state, the pressurization toCircuit Board T1 for inspection was released while retaining thetemperature of the test table at 85° C., and Circuit Board T1 forinspection was retained for 30 seconds in this state. This process wasregarded as a cycle, and the cycle was repeated 50,000 times in total.

The results are shown in Table 2.

After the above-described durability test was completed, Sheet-likeConnector M(1-1), Sheet-like Connector M(1-2) and Sheet-like ConnectorM(1-4) were respectively observed. As a result, it was confirmed thatnone of the electrode structures fell off from the insulating sheet, andso these sheet-like connectors have high durability.

Comparative Example 1

A sheet-like connector was produced in the same manner as in Example 1except that the whole of the first front surface-side metal layer wasremoved by the etching treatment to form no holding part in theproduction of the sheet-like connector.

The sheet-like connector thus obtained is such that the thickness d ofthe insulating sheet is 12.5 μm, the shape of the front-surfaceelectrode part in each of the electrode structures is a truncated coneshape, the diameter of a base end thereof is 45 μm, the diameter of atip end thereof is 17 μm, the projected height thereof is 25 μm, theshape of the short circuit part is a truncated cone shape, the diameterof one end on the front surface side thereof is 45 μm, the diameter ofthe other end on the back surface side is 60 μm, the shape of theback-surface electrode part is a rectangular flat plate shape, the widththereof is 60 μm, the length thereof is 150 μm, and the thickness is 30μm.

In such a manner, 5 sheet-like connectors in total were produced. Thesesheet-like connectors are referred to as “Sheet-like Connector M(2-1)”to “Sheet-like Connector M(2-5)”.

Sheet-like Connector M(2-1) to Sheet-like Connector M(2-5) weresubjected to the connection stability test in the same manner as inExample 1. The results are shown in Table 1.

Sheet-like Connector M(2-1) and Sheet-like Connector M(2-3) weresubjected to the durability test in the same manner as in Example 1. Theresults are shown in Table 2.

After the durability test was completed, Sheet-like Connector M(2-1) andSheet-like Connector M(2-3) were respectively observed. As a result, itwas found that 52 electrode structures among 15,496 electrode structurein Sheet-like Connector M(2-1) fell off from the insulating sheet, and16 electrode structures among 15,496 electrode structure in Sheet-likeConnector M(2-3) fell off from the insulating sheet.

Comparative Example 2

A sheet-like connector was produced in the following manner inaccordance with the process shown in FIG. 50.

A laminate material was provided by laminating a copper layer having athickness of 5 μm on one surface of an insulating sheet formed ofpolyimide and having a thickness of 12.5 μm, and 15,496 through-holeseach extending through in the thickness-wise direction of the insulatingsheet and having a diameter of 30 μm were formed in the insulating sheetof the laminate material in accordance with a pattern corresponding tothe pattern of electrodes to be inspected in Wafer W1 for test bysubjecting the insulating sheet to laser machining. This laminatematerial was then subjected to photolithography and plating treatmentwith nickel, whereby short circuit parts integrally linked to the copperlayer were formed in the through-holes in the insulating sheet, and atthe same time, protruding front-surface electrode parts integrallylinked to the respective short circuit parts were formed on the frontsurface of the insulating sheet. The diameter of a base end of each ofthe front-surface electrode parts was 70 μm, and the height from thesurface of the insulating sheet was 20 μm. Thereafter, the copper layerof the laminate material was subjected to a photo-etching treatment toremove a part thereof, thereby forming rectangular back-surfaceelectrode parts having dimensions of 60 μm×150 μm. Further, thefront-surface electrode parts and back-surface electrode parts weresubjected to a plating treatment with gold, thereby forming electrodestructures, thus resulting in the production of a sheet-like connector.

In such a manner, 5 sheet-like connectors in total were produced. Thesesheet-like connectors are referred to as “Sheet-like Connector M(3-1)”to “Sheet-like Connector M(3-5)”.

Sheet-like Connector M(3-1) to Sheet-like Connector M(3-5) weresubjected to the connection stability test in the same manner as inExample 1. The results are shown in Table 1.

Sheet-like Connector M(3-1), Sheet-like Connector M(3-2) and Sheet-likeConnector M(3-4) were subjected to the durability test in the samemanner as in Example 1. The results are shown in Table 2.

TABLE 1 Proportion of measuring points, at which the conductionresistance was lower than 1 Ω, to all measuring points (%) Load: 12.4 kgLoad: 31 kg Example 1 Sheet-like Connector M (1-1) 100 100 Sheet-likeConnector M (1-2) 100 100 Sheet-like Connector M (1-3) 100 100Sheet-like Connector M (1-4) 100 100 Sheet-like Connector M (1-5) 100100 Com- Sheet-like Connector M (2-1) 100 100 parative Sheet-likeConnector M (2-2) 96 96 Example 1 Sheet-like Connector M (2-3) 100 100Sheet-like Connector M (2-4) 99 99 Sheet-like Connector M (2-5) 92 95Com- Sheet-like Connector M (3-1) 89 100 parative Sheet-like Connector M(3-2) 93 100 Example 2 Sheet-like Connector M (3-3) 77 97 Sheet-likeConnector M (3-4) 90 100 Sheet-like Connector M (3-5) 88 97

Number of points at which the conduction resistance was 1 Ω or higher(count) Number of 1,000 5,000 10,000 30,000 50,000 cycle(s) 1 time timestimes times times times Example 1 Sheet-like Connector M(1-1) 0 0 0 0 00 Sheet-like Connector M(1-2) 0 0 0 0 0 0 Sheet-like Connector M(1-4) 00 0 0 0 0 Comparative Sheet-like Connector M(2-1) 0 2 4 38 74 128Example 1 Sheet-like Connector M(2-3) 0 0 2 18 32 42 ComparativeSheet-like Connector M(3-1) 0 0 0 0 0 0 Example 2 Sheet-like ConnectorM(3-2) 0 0 0 0 4 16 Sheet-like Connector M(3-4) 0 0 0 2 2 8

As apparent from the results shown in Table 1, it was confirmed thataccording to Sheet-like Connector M(1-1) to Sheet-like Connector M(1-5)of Example 1, a stable electrically connected state is surely achievedto all electrodes to be inspected by a small load.

It was also confirmed that the sheet-like connectors according toExample 1 have high durability.

1. A sheet-like connector comprising an insulating sheet and a pluralityof electrode structures arranged in the insulating sheet in a stateseparated from one another in a plane direction of the insulating sheetand extending through in a thickness-wise direction of the insulatingsheet, wherein each of the electrode structures includes, afront-surface electrode part exposed to a front surface of theinsulating sheet and projected from the front surface of the insulatingsheet, a back-surface electrode part exposed to a back surface of theinsulating sheet, a short circuit part continuously extending from thebase end of the front-surface electrode part through the insulatingsheet in the thickness-wise direction thereof and linked to theback-surface electrode part, the front-surface electrode part and theshort circuit part formed of a metal, and a holding part continuouslyextending from a base end portion of the front-surface electrode partoutward along the front surface of the insulating sheet, and including ametal layer having a thickness of 3 to 12 μm formed on the insulatingmaterial, the metal forming the front-surface electrode part and theshort circuit part is a different metal than the metal forming theholding part.
 2. The sheet-like connector according to claim 1, whereinthe front-surface electrode part in the electrode structure has a shapethat the diameter becomes gradually small from the base end thereoftoward the tip end.
 3. The sheet-like connector according to claim 1,wherein the value of a ratio R₂/R₁ of the diameter R₂ of the tip end ofthe front-surface electrode part in the electrode structure to thediameter R₁ of the base end of the front-surface electrode part is 0.11to 0.55.
 4. The sheet-like connector according to claim 1, wherein thevalue of a ratio h/R₁ of the projected height h of the front-surfaceelectrode part in the electrode structure to the diameter R₁ of the baseend of the front-surface electrode part is 0.2 to
 3. 5. The sheet-likeconnector according to claim 1, wherein the short circuit part in theelectrode structure has a shape that the diameter becomes graduallysmall from the back surface of the insulating sheet toward the frontsurface thereof.
 6. The sheet-like connector according to claim 1,wherein the insulating sheet is composed of an etching-capable polymericmaterial.
 7. The sheet-like connector according to claim 6, wherein theinsulating sheet is composed of polyimide.
 8. A probe for circuitinspection for conducting electrical connection between a circuit devicethat is an object of inspection and a tester, which comprises: a circuitboard for inspection, on which a plurality of inspection electrodes havebeen formed according to electrodes to be inspected of a circuit device,which is an object of inspection, an anisotropically conductiveconnector arranged on the circuit board for inspection, and thesheet-like connector according to claim 1, which is arranged on theanisotropically conductive connector.
 9. The probe for circuitinspection according to claim 8, wherein the circuit device that is theobject of inspection is a wafer, on which a great number of integratedcircuits have been formed, and the anisotropically conductive connectorhas a frame plate having a plurality of openings formed correspondinglyto electrode regions, in which electrodes to be inspected in the wholeor part of the integrated circuits formed on the wafer, which is theobject of inspection, have been arranged, and anisotropically conductivesheets arranged so as to close the respective openings in the frameplate.
 10. An inspection apparatus for circuit devices, which comprisesthe probe for circuit inspection according to claim
 8. 11. Thesheet-like connector according to claim 1, wherein the metal of thefront-surface electrode and the short circuit part are formed byplating.
 12. The sheet-like connector according to claim 1, wherein themetal layer of the holding part is formed by etching.
 13. The sheet-likeconnector according to claim 1, wherein the metal of the front-surfaceelectrode and the short circuit part are selected from a groupconsisting of nickel, gold, silver, palladium, and iron, and the metalforming the holding part is copper.
 14. An electrode structurecomprising: a front-surface electrode part exposed to a front surface ofan insulating sheet and projected from the front surface of theinsulating sheet; a back-surface electrode part exposed to a backsurface of the insulating sheet; a short circuit part continuouslyextending from the base end of the front-surface electrode part throughthe insulating sheet in the thickness-wise direction thereof and linkedto the back-surface electrode part, the front-surface electrode part andthe short circuit part formed of a metal; and a holding partcontinuously extending from a base end portion of the front-surfaceelectrode part outward along the front surface of the insulating sheet,and including a metal layer having a thickness of 3 to 12 μm formed onthe insulating material, the metal forming the front-surface electrodepart and the short circuit part is a different metal than the metalforming the holding part.